AP Chemistry vocabulary
property
any characteristic that allows us to recognize a particular type of matter and distinguish it from other types
force
any kind of push or pull exerted on an object
how to use the activity series to predict the outcome of reactions between metals and either metal salts or acids:
any metal on the list can be oxidized by the ions of elements below it.
amphiteric
any molecule or ion that can either gain or lose a proton
insoluble
any substance with a solubility less than 0.01 mol/ L. the attraction between the oppositely charged ions in the solid is too great for the water molecules to separate them to any significant extent, and the substance remains largely undissolved.
The three quantum numbers of the quantum mechanical model
are n, l, and ml, used to describe an orbital.
electrostatic potential energy
arises from the interactions between charged particles.
unlocalized bonding
arises in molecules that have 2 or more resonance structures involving pi bonds.
How to calculate formal charge of any atom in a Lewis structure
assign the electrons to the atom as follows: 1) All unshared (nonbonding) electrons are assigned to the atom on which they are found. 2.) for any bond- single, double, triple- half the bonding electrons are assigned to each atom in the bond. 3.) subtract the number of electrons assigned to the atom from the number of valence electrons in the isolated atom. these are the formal charges. 4.) the formal charges on a neutral molecule add to zero, whereas those on an ion add to give the overall charge of the ion. guidelines to choose the correct one: 1.) we generally choose the lewis structure in which the atoms bear formal charges closest to zero. 2.) we generally choose the lewis structure in which any negative charges reside on the more electronegative atoms. -formal charges do not represent real charges on atoms. these are just a bookkeeping convention.
quantitative properties
associated with numbers
whenever a fast step precedes a slow one, we can solve for the concentration of an intermediate by
assuming that an equilibrium is established in the first step
submicroscopic
atoms and molecules
The Octet Rule
atoms often gain, lose, or share electrons to achieve the same number of electrons as the noble gas closest to them on the periodic table. (until they are surrounded by 8 valence electrons). Can be thought of as 4 pairs of valence electrons arranged around the atom.
metal oxides are _____ (acidic or basic)
basic due to the oxide ion
active site
biochemical reaction catalyzed at a specific location
what two things define a molecule's shape and size?
bond lengths and bond angles
exothermic reaction
bonds in the products are stronger than in the reactants
for a molecule that consists of more than 2 atoms, the dipole moment depends on
both the polarities of the individual bonds and the geometry of the molecule
Application of Hess's Law
breaking bonds is always endothermic. bond formation is exothermic.
the actinide elements
built up by completing the 5f orbitals after the 5d, 6p, and 7s. they are radioactive, and most of them are not found in nature.
dimensional analysis
carry units through calculations. using this helps ensure that the solutions to problems yield the proper units.
ABn
central atom A bonded to n B atoms
precipitation reactions occur when:
certain pairs of oppositely charged ions attract each other so strongly that they form an insoluble ionic solid.
sublime
change directly from solid to vapor
the solution process involves two factors:
change in enthalpy, change in entropy
reaction rate
change in the concentration of reactants or products per unit time (molarity over time- M/s)
down a period the effective nuclear change
changes little because the atomic radius increases, but the attraction between the nucleus and the electron decreases. This causes the ionization energy to decrease.
Ka for hydrolysis reactions increases with increasing _____ and decreasing _______
charge, radius of ion
enthalpy of reaction deltaHrxn
coefficients in the balanced equation represent the number of moles of reactants and products producing the associated enthalpy change.
delta H reaction standard =
coefficients x delta H standard formation products - coefficients x delta H standard formation reactants
bimolecular
collision of 2 reactant molecules involved
termolecular
collision of 3 reactant molecules (rare)
pressure is caused by:
collisions of molecules of gas with the walls of the container. the magnitude of the pressure is determined by how often and how forcefully the molecules strike the walls.
To determine the direction in which the reaction will proceed to achieve equilibrium, we
compare the values of Qc and Kc or Qp and Kp
to predict whether certain combinations of ions form insoluble compounds we...
consider the solubility rules for common ionic compounds
elements
contribute to the variety of matter in our world. cannot be decomposed into simpler substances, composed of only one kind of atom.
the Lewis theory
covalent bonding = atoms share electrons such sharing concentrates electron density between 2 nucleus
dipole moments are usually reported in
debyes, a unit that equals 3.34 x 10^-30 coulomb-meters (C-m)
bond angles ______ as the number of nonbonding electron domains increases.
decrease
most metal ions can also react with water to ________ the pH of an aqueous solution
decrease
reduction occurs when there is a _________ in the oxidation number of an atom
decrease
higher temp > greater KE > attractive forces between molecules overcomed > viscosity ___
decreases
the solubility of gases in water ________ with increasing temperature
decreases
when the electron moves farther from the nucleus, the force of attraction
decreases
nonbonding pair/ lone pair
defines an electron domain that is located principally on one atom
solid
definite shape ad definite volume, cannot compressed to an extent, molecules held tightly together in definite arrangements, only vibrate slightly in other wise fixed positions
enthalpies of combustion
delta H combusting in O2
enthalpies of fusion
delta H for melting solids
enthalpies of formation
delta H formation of a compound from its constituent elements
standard enthalpy of formation
delta Hf. change in enthalpy for the reaction that forms one mole of the compound from its elements, with all substances in their standard states
deltaHsoln =
deltaH1 + deltaH2 + deltaH3
molality
denoted m, is a concentration unit that equals the number of moles of solute per kilogram of solvent.
spin magnetic quantum number
denoted ms, with two possible values: +1/2, -1/2. The two opposite directions of spin produce oppositely directed magnetic fields by the spinning charge, which leads to the splitting of spectral lines into closely spaced pairs.
the van der waals equation
departures from ideal behavior can be too large for the ideal gas equation 1. for a real gas this expression would have to be corrected for the finite volume and 2. for the attractive forces between gas molecules. P = (nRT / V - nb) - (n^2a/ V^2) b= correction for volume of molecules (in L/mol) a = correction for attractive forces between pairs of molecules (in L^2-atom / mol^2) a and b are different for each gas and generally increase with an increase in the mass of the molecule, complexity in its structure. larger molecules = larger volumes = greater IMFs
extensive properties
depend on and relate to the quantity, or amount of the sample, or the substance, present, with two examples being mass and volume
rate constant K
determines how temperature affects the rate
heat capacity
determines temperature change experienced by an object when it absorbs a certain amount of heat / amount of heat required to raise its temperature by 1 K (or 1 degree C)
calorimeter
device used to measure heat flow
dispersion forces between polar molecules contribute more to IMF attractions than ________
dipole dipole
polar liquids tend to dissolve readily in polar solvents because of _______
dipole dipole attractions between solvent molecules and solute molecules
bond dipole
dipole moment that is due only to the two atoms in one bond of a molecule
comparing intermolecular forces
dispersion forces are found in all substances -strength increases with increased molecular weight and depend on molecular shapes dipole dipole forces add to the effect of dispersion forces and are found in polar molecules hydrogen bonds require H bonded to F, O, or N and add to the effect of dispersion forces (strongest IMF) ionic/ covalent bonds are the strongest IMFs
liquid
distinct volume (independent of container) but no specific shape. assumes shape of container it occupies. cannot be compressed to an extent. molecules packed closer together. still move rapidly, slide over each other
cations of strong bases
don't react with water or affect pH.
although the alkali metal ions are colorless,
each emits a characteristic color when placed in a flame. the high temperature of the flame excites the valence electron to a high energy orbital, causing the atom to be in an excited state.
orbital diagram
each orbital is denoted by a box, and an electron by a half arrow. an arrow pointing up has ms = +1/2 and an arrow pointing down has ms = -1/2 for the two electrons in the orbital. electrons are said to be paired.
orbitals
each represents a specific distribution of electron density in space, as given by it's probability density. each has a characteristic energy and shape. It is not the same as an orbit in Bohr's model.
polarizability
ease with which electron distribution in a molecule is distorted into a temporary dipole.
subatomic particles
electrically charged particles that compose atoms.
lewis base
electron pair donor
oxidation- reduction reactions, or redox reactions
electrons are transferred between reactants
ionic bond
electrostatic forces that exist between ions of opposite charge. formed from atoms by the transfer of one or more electrons from one atom to another. Generally between metals and nonmetals.
product has higher energy than reactant..._____thermic
endothermic
the loss of electrons from an atom is always an ________ process
endothermic. energy is required to remove an electron.
the first law of thermodynamics
energy is conserved. energy cannot be created or destroyed
heat of vaporization
energy required to transition a liquid into the gaseous state.
Heat
energy transferred from a hotter object to a colder one / energy transferred between a system and its surroundings as a result of their difference in temperature
work
energy used to cause an object to move against a force/ energy transferred when an object is moved by a force. W = Fd
the equivalence point
equal moles base and acid reacted, leaving solution of their salt. pH equals 7.00.
surroundings
everything else
ion-dipole
exists between an ion and the partial charge on the end of a polar molecule. positive ions attracted to negative end of dipole negative end of dipoles oriented toward a cation negative ions attracted to positive end of dipole positive end of dipole oriented toward an anion magnitude of the attraction increases as : the charge of the ion increases or the magnitude of the dipole moment increases important for solutions of ionic substances in polar liquids, like NaCl in water.
product has lower energy than reactant... ___thermic
exothermic
quantum theory
explains much of the behavior of electrons in atoms
when n is 4 or greater, there are 7 equivalent ___ orbitals
f
changes in concentration of reactant produces proportional change in the rate = _______ order
first order
colors of halogens
fluorine gas is pale yellow chlorine gas is yellow-green bromine liquid is reddish brown and forms that color vapor solid iodine is grayish black and forms a violet vapor
Hund's Rule
for degenerate orbitals, the lowest energy is attained when the number of electrons with the same spin is maximized. electrons will occupy orbitals singly to the maximum extent possible. Electrons will be arranged to have parallel spins--single electrons in a given subshell will have the same spin magnetic quantum number. This is based on the fact that electrons repel eachother. By occupying different orbitals, the electrons remain as far as possible from one another, thus minimizing electron-electron repulsions.
pliable solid substance
for example, plastic. these do not behave like ionic substances. they have a different model of bonding between atoms.
intermolecular forces
forces that exist between molecules
metallic solids
form of unit particles: metal atoms forces between particles: metallic bonds properties: soft to very hard, low to very high melting point, excellent thermal and electrical conduction because of mobility of electrons, malleable and ductile examples: metallic elements- Cu, Fe, Al, etc. more: strength of bonding increases as number of electrons available for bonding increases. usually hexagonal or cubic close packed or body centered cubic structures. 8-12 adjacent atoms positive ions in a sea of delocalized valence electrons
ionic solids
form of unit particles: positive and negative ions forces between particles: electrostatic attractions properties: hard and brittle, high melting point, poor thermal and electrical conduction examples: typical salts--for example, NaCl, Ca(NO3)2 more: strengths of ionic bond depends on charges of ion structure of solid depends on charges and relative sizes of ions larger size: larger coordination #
conjugate acid
formed by adding a proton to the base
conjugate base
formed by removing a proton from the acid
intermediate
formed in one elementary reaction and consumed in the next
net ionic equation
formed when spectator ions are omitted from the complete ionic equation. it includes only the ions and molecules directly involved in the reaction. charge is conserved. the sum of the charges of the ions must be the same on both sides of a balanced net ionic equation
metallic bond
found in metals like copper, iron, and aluminum. Each atom in a metal is bonded to several neighboring atoms. Bonding electrons are relatively free to move throughout the 3d structure of the metal. They give rise to such typical metallic properties as high electrical conductivity and luster.
nonmetal atoms tend to...
gain electrons to form anions
the decomposition of unstable carbonic acids causes
gas bubbles (CO2) to be produced
condensation
gas to liquid
deposition
gas to solid
prefixes of units
giga mega kilo hecto deka (base unit) deci centi milli micro nano pico femto
quantum
given by Planck, it means "fixed amount", to the smallest quantity of energy that can be emitted or absorbed by atoms as electromagnetic radiation.
ionic bond nomenclature
given names based on their component ions, including charge of the cation if that charge is variable.
how to calculate empirical formulas
given: mass % of elements assume a 100 gram sample find the grams of each element use the molar mass to convert grams of each element into moles of each element calculate the mole ratio by dividing the larger number of moles by the smaller. this ratio is the empirical formula because its subscripts are the smallest integers that express the ratios of atoms present in the compound.
unit for density
grams per cubic cm = g/cm3 OR g/mL
Conversion sequence for converted the coefficients in a chemical equation and their representation of the relative numbers of molecules involved in a reaction into the masses of the substances
grams reactant > moles reactant > moles product (using coefficients of reactant and product from balanced equation) > grams product
atmospheric pressure
gravity causes the atmosphere to push down on the earth
greater IMFs > _______ critical temp
greater
the faster molecules are moving, the _____ the likelihood of hitting the hole and effusing
greater
lamda = h/mv
h is planck's constant the quantity mv for any object is called its momentum. this is used to find the characteristic wavelength of the electron or of any other particle
the _____ , which are one electron shy of a filled p subshell, have the most negative electron affinities
halogens
strong attractions cause ionic materials to be
hard, brittle, and have high melting points
alkaline earth metal properties
harder and more dense melt at higher temperatures their first ionization energies are low, but not as low as those of the alkali metals they are less reactive than the alkali metals because the ease with which elements lose electrons decreases as we move across the periodic table from left to right and increases as we move down a group tendency to lose their two outer s electrons and form 2+ ions
molecules in a sample of gas have average kinetic energy and average speed but individual molecules at any instant
have a wide range of speeds.
metalloids
have properties that fall between those of metals and those of nonmetals.
When naming binary compounds...
he name of the less electronegative element is first. the name of the more electronegative element then follows, modified to have an "ide" ending.
specific heat
heat capacity of one GRAM of a substance. C = q / m x deltaT or q = mCdeltaT
molar heat capacity
heat capacity of one mole of a substance
enthalpy
heat content
fuel value
heat released when one gram of the substance is combusted
alpha
heavier than an electron, having a mass about 730 times that of an electron. Have a charge of 2+.
bond polarity
helps describe the sharing of electrons between atoms.
high frequency and short wavelength = ______ energy
high energy
Gamma
high energy radiation similar to X rays; it does not consist of particles and carries no charge.
Beta
high speed electrons and can be considered the radioactive equivalent of cathode rays. Negative charge of 1-.
for some elements, such as the noble gases, the electron affinity has a positive value, meaning the anion is ______ in energy than are the separated atom and electron
higher
smaller atoms have ______ ionization energies.
higher
stronger IMFs = _______ boiling point
higher
weaker IMFs > large number of molecules escape > ______ vapor pressure
higher
Density = PM / RT
higher M and P = more dense higher T = less dense M = molar mass
accuracy
how closely individual measurements agree with the correct, or true value
bond polarity is a measure of
how equally the electrons in a bond are shared between the two atoms of the bond.
the exponents in a rate law indicate...
how the rate is affected by the concentration of each reactant.
atomic orbital set: s, p, p, p, d
hybrid orbital set: five sp3d geometry: trigonal bipyramidal
atomic orbital set: s, p , p, p
hybrid orbital set: four sp3 geometry: tetrahedral
atomic orbital set: s, p, p, p, d, d
hybrid orbital set: six sp3d2 geometry: octahedral
atomic orbital set: s, p, p
hybrid orbital set: three sp2 geometry: trigonal planar
atomic orbital set: s, p
hybrid orbital set: two sp geometry: linear
because metal ions are positively charged, they attract the unshared electron pairs of water. this process is called
hydration
why real gases deviate from ideal behavior
ideal- occupy no space, no attractions real- finite volumes, attract one another
hypotonic
if one solution is of lower osmotic pressure, separated by a higher concentrated solution through a semi permeable membrane, it is said to be this.
atomic weight
if the chemical formula is merely the chemical symbol of an element, such as Na, then the formula weight equals this weight.
molecular weight
if the chemical formula is that of a molecule, then the formula weight is also this weight. For example, C6H12O6 (glucose) is 180.0 amu.
law of multiple proportions
if two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers.
unsaturated
if we dissolve less solute than that needed to form a saturated solution. it has the capacity to dissolve more solute.
osmotic pressure
in a solution, the pressure required to prevent osmosis by pure solvent it obeys a law similar to the ideal gas law: (pi)V = nRT
most transition metals have more than 3 e- beyond a noble gas core.
in forming ions, transition metals lose the valence shell s electrons first, then as many d electrons are required to reach the charge of the ion.
alkanes
in the most basic class of hydrocarbons, each carbon atom is bonded to four other atoms
Haber Process
in the presence of a catalyst, N2 and H2 are combined at a pressure of several hundred atmospheres and a temperature of several degrees Celsius N2 (g) + 3 H2 (g) <--> 2 NH3
aromatic
include the hydrocarbon called benzene, C6H6. six C atoms are bonded in a hexagonal ring. One H atom bonded to each C atom. Each structure shows C-C single bonds and 3 C=C double, which can be in different places.
amphoteric oxides and bases
include those of Al3+, Cr3+, Zn2+, and Sn2+ (dissolve in strongly acidic or basic solution)
Schrodinger's Wave Equation
incorporates both the wavelike behavior and the particle like behavior of the electron
oxidation occurs with an ________ in the oxidation number of an atom
increase
tripling the concentration causes the rate to ... (if the reactant is 2nd order)
increase ninefold 3^2 = 9
across a period, electronegativity
increases with some exceptions
Within each period of the periodic table, the first ionization energy generally _________ with increasing atomic number.
increases.
E depends on only the _ and _ states of a system
initial and final states
initial rate
instantaneous rate at t=0
if the slow step is not the first one, the faster proceeding steps produce___
intermediate products that accumulate before being consumed in the slowest step.
barometer
invented by Evangelista Torricelli to show that the atmosphere has weight. 1. glass tube 760 mm long 2. closed at one end, filled with mercury. 3. inverted into a dish with more mercury 4. some mercury flows out when the tube is inverted 5. A column of mercury remains in the tube 6. No air above mercury in the tube 7. Mercury pushed up the tube until pressure at the base of the tube due to mass of mercury balances the atmospheric pressure. 8. Height of mercury column = measure of atmospheric pressure
the magnitude of lattice energy depends primarily on the ionic charges because
ionic radii do not vary over a very wide range.
ion-dipole forces dominate in solutions of...
ionic substances in water
as an ionic compound dissolves in water:
ions are surrounded by H2O molecules ions are said to be solvated
hydrolysis
ions react with water generate H+ or OH-
large, positive lattice energy =
ions strongly attracted to one another
spectator ions
ions that appear in identical forms among both the reactants and products of a complete ionic equation
the strength of a covalent bond between 2 atoms
is determined by the energy required to break that bond. it is easiest to relate bond strength to the enthalpy change in reactions in which bonds are broken.
whenever you see the formula of a compound containing a metal in a high oxidation state, (usually above 3+), you should not be surprised if
it exhibits the general properties of molecular, rather than ionic, compounds.
How to find the total pressure at constant temperature and volume
it is determined by the total number of moles of gas present, whether that total represents just one substance or a mixture. Pt = (n1 + n2 + n3...) RT / V = nt (RT/ V)
this attraction between the electron and the nucleus causes
it to become harder to remove the electron. the ionization energy increases.
the partial pressure of a gas in a mixture is
its mole fraction times the total pressure
the solubility of a gas increases in direct proportion to
its partial pressure above the solution
The Arrhenius Equation
k = Ae ^-Ea/RT For most reactions the increase in rate with increasing temperature is nonlinear
What is the SI unit for force?
kg-m/s^2 = Newton (N)
SI unit for mass
kilogram
Effective nuclear charge explains that for a many electron atom, the energies of orbitals with the same n value increase with increasing _ values..
l
azimuthal quantum number
l 1. can have integral values from 0 to n-1 for each value of n. 2. this quantum number defines the shape of the orbital. 3. it is generally designated by the letters s, p, d, and f, corresponding to l values of 0, 1, 2, and 3, respectively
in a many electron atom, for a given value of n, the energy of an orbital increases with an increasing value of
l. the electron electron repulsions cause the different subshells to be at different energies.
macroscopic
large, ordinary sized objects.
how can size play an important role in determining whether an atom in a molecule or polyatomic ion can accommodate more than 8 electrons?
larger central atom > larger number of electrons can surround it number of molecules and ions with expanded valence shells therefore increases with increasing size of the central atom the size of the surrounding atoms is also important: expanded valence shells occur most often when the central atom is bonded to the smallest and most electronegative atoms, such as F, Cl, and O.
anions are ______ than their parent atoms.
larger. when electrons are added to a neutral atom to form an anion, the increased electron-electron repulsions cause the electrons to spread out more in space.
acidity increases with the electronegativity of element X, generally from ___ to ______ in a row
left to right
If k << 1, the equilibrium lies to the
left- reactants predominate
2 bonding, 3 non bonding electron domains
linear
AB2
linear or bent
two electron domains are arranged
linearly
vaporization
liquid to gas
freezing
liquid to solid
Activation energy can be determined from (without graphing)
lnK1/K2 = Ea/R (1/T2 - 1/T1) calculate rate constant K1 at some temp T, when we know activation energy and rate constant K2, at some other temp, T2.
We can determine half life by substituting [A]t1/2 into...
ln[A]t - ln [A]0 = -kt or ln [A]t/[A]0 = -kt
to form the bond with H+, a ______ is necessary
lone pair
shapes influence magnitude of dispersion forces
long, cylinder shape - greater attraction compact, sphere shape - less attraction
metal atoms tend to...
lose electrons to form cations
long wavelength = ______ frequency
low
adding a nonvolatile solute to a solvent always ______ the vapor pressure
lowers
molecule
made when two or more atoms are joined together in specific shapes
the dipole moment increases as the...
magnitude of charge that is separated increases and as the distance between the charges increases.
the solvent must be strong enough to _____________ in order for a solution to form
make deltaH3 comparable in magnitude to deltaH1 + deltaH2
energy released by the attraction between ions of unlike charge more than makes up for the endothermic nature of ionization energies...
making the formation of ionic compounds an exothermic process.
predicting ionic charges
many atoms gain or lose electrons so as to end up with the same number of electrons as the noble gas closes to them in the periodic table the charges of ions relate to their position in the periodic table
Formula for density
mass / volume
semipermeable
materials when, in contact with a solution, allow some molecules to pass through their network of tiny pores, but not others. they generally allow some small solvent molecules such as water to pass through, but block larger solute molecules or ions
temperature
measure of the hotness or coldness of an object physical property that determines the direction of heat flow
Activation energy can be determined from
measuring k at a series of temps, graphing lnk vs 1/T, calculating Ea from the slope of the line.
properties of halogens
melting and boiling points increase with increasing atomic number fluorine and chlorine are gases at room temperature bromine is a liquid iodine is a solid highly negative electron affinities- tendency to gain electrons from other elements to form halide ions.
metal oxides that dissolve in water react to form
metal hydroxides
reactions between alkali metals and oxygen produce
metal oxides
metal carbonates decompose to form...
metal oxides and carbon dioxide when heated
nonsoluble alkali metals react with oxygen to form
metal peroxides, which contain the O2 2- ion (peroxide)
Elements that lie along the line that separates metals from nonmentals are
metalloids
because of their electron affinities, nonmetals tend to gain electrons when they react with ____
metals
SI unit for length
meter
filtration
mixture of a solid and a liquid is poured through a pourous medium, in this case filter paper. The liquid passes through the paper while the solid remains on the paper
homogeneous / solutions
mixtures that are uniform throughout
the magnetic quantum number
ml 1. can have integral values between -1 and 1, including 0. 2. this quantum number describes the orientation of the orbital in space.
virtually all substances that are liquids at room temperature are
molecular substances
differences in the magnitudes of the attractive forces can usually be associated with differences in
molecular weights
double and triple bonds (and hence pi bonds) are more common in
molecules made up of small atoms, especially C, N, and O.
mole fraction of component=
moles of component / total moles of all components. the symbol X is used to express this.
formula for molarity
moles solute / liters solution depends on volume of solution
how to determine the number of moles of a substance with known molarity
moles solute = M x L
prefixes of molecular compounds
mono di tri tetra penta hexa hepta octa nona deca
molecular substances that have aqueous solutions that contain ions
most are acids.
properties of metals
most exhibit a shiny luster conduct heat and electricity malleable (can be pounded into thin sheets) ductile (can be drawn into wires) all are solids at room temperature except mercury, which is a liquid. most melt at very high temperatures
when the neutralization steps of a polyprotic acid or a polyprotic base are sufficiently separated, the substance exhibits a titration curve with
multiple equivalence points
how to obtain the number of atoms of each type by looking at a chemical equation?
multiplying the coefficient and the subscripts associated with each element in the chemical formula
the shell with principle quantum number n will consist of exactly __ subshells
n
the principal quantum number
n 1. can have positive integral values of 1,2,3 2. as n increases, the orbital becomes larger. The electron spends more time farther from the nucleus. 3. An increase in n also means that the electron has a higher energy and is therefore less tightly bound to the nucleus.
each subshell corresponds to a different allowed value of l from 0 to
n-1
the total number of orbitals in a shell is ___
n^2, where n is the principal quantum number of the shell.
molecular bond nomenclature
named using prefixes to indicate the number of atoms of each kind in the substance.
the greater the attraction between a given atom and an added electron, the more _____ the atom's electron affinity.
negative
the heat of formation of ionic compounds is quite
negative, very exothermic.
If HX is a strong acid, X- will have a ________ tendency to abstract protons from water to produce hydroxide
negligible (will not affect pH of solution)
network solids like diamond and quartz are ______ in either polar or nonpolar solvents because __________
network solids like diamond and quartz are not soluble in either polar or nonpolar solvents because of the strong bonding forces within the solid.
If [H+] = [OH-], the solution is
neutral
gas/ vapor
no fixed volume or shape, conforms to volume and shape of container, can be compressed to occupy smaller volume or expand to occupy a larger one, molecules are far apart and moving at high speeds, colliding repeatedly with each other and container
only the _______ elements are found in nature as isolated atoms
noble gas
properties of noble gases
nonmetals that are gases at room temperature monatomic- consist of single atoms rather than molecules have completely filled s and p subshells large first ionization energies, decrease down the column unreactive- stable electron configurations
molecules in which the central atom is symmetrically surrounded by identical atoms are
nonpolar
attraction between the electrons of an atom and the nucleus is order
ns < np <nd
atomic weights generally increase with increasing atomic
number
the increase in boiling point relative to that of the pure solvent is directly proportional to the
number of solute particles per mole of solvent molecules (molality) deltaTb = Kbm Kb = the molal boiling point elevation constant
exact numbers
numbers that can be counted
static equilibrium
object at rest
scientific method
observations and or experiments find patterns, trends laws test hypothesis and or formulate it theory
the internuclear distance at the minimum of a potential energy curve corresponds to the
observed bond length
ionization of diprotic acids
occurs in two steps. H2SO4 > H+ + HSO4 - HSO4 > H+ + SO4 2- (aqueous solutions of sulfuric acid contain a mixture of H+, HSO4-, and SO4 2-
chemical equilibrium
occurs when opposing reactions are proceeding at equal rates: the rate at which the products are formed from the reactants = rate at which the reactants are formed from the products.
anomalous electron configurations
occurs when there are enough electrons to lead to precisely half filled sets of degenerate orbitals, for example, Chromium [Ar]3d^5 4s^1 instead of [Ar]3d^4 4s^2, or to completely fill a d subshell, as in copper [Ar]3d^10 4s^1 instead of [Ar]3d^9 4s^2
six electron domains are arranged
octahedrally
the overall dipole moment
of a polyatomic molecule is the vector sum of its bond dipoles
The pH of a solution of a weak acid is higher than that of a solution....
of a strong acid of the same molarity.
prefixes for a series of oxyanions
one more oxygen atom than the oxyanion ending in ate- the prefix per- is added one oxygen atom fewer than the oxyanion ending in ite- the prefix hypo- is added.
polar covalent bond
one of the atoms exerts a greater attraction for the bonding electrons than the other. If the difference in relative ability to attract electrons is large enough, an ionic bond is formed.
decomposition reaction
one substance undergoes a reaction to produce two or more substances. many compounds undergo decomposition reactions when heated.
autoionization of water
one water molecule can donate proton to another water molecule. The reactions are rapid in both directions. At room temperature, only 2 out of every 10^9 molecules are ionized at any given instant
a first order reaction
one whose rate depends on the concentration of a single reactant raised to the first power
a second order reaction
one whose rate depends on the reactant concentration raised to the second power or on the concentration of two different reactants, each raised to the first power.
weak acids
only partially dissociate in aqueous solution, exist as a mixture of acid molecules and their ions. Conjugate bases are weak bases.
degenerate
orbitals with the same energy are said to be ____
oxygen has a tendency to attract electrons from other elements to
oxidize them
metals lose electrons, or are ______ when they undergo chemical reactions
oxidized
when an atom, ion, or molecule has become more positively charged, or lost electrons, we say that it has been...
oxidized
We try to select a buffer whose acid form has a pKa close to the desired
pH
Henderson Hasselbach Equation
pH = pKa + log[base]/[acid] equilibrium concentrations^
after the equivalence point
pH determined by concentration of excess acid or base.
pKa + pKb =
pKw, 14.00 @ 25 degrees C
immiscible
pairs of liquids that do not dissolve in one another
miscible
pairs of liquids that mix in all proportions
Dalton's law of partial pressures
partial pressure= the pressure exerted by a particular component of a mixture of gases. Pt = P1 + P2 + P3....
delocalized
pi bonds that extend over more than two bonded atoms
pi bonds require that portions of a molecule be ___, introducing rigidity into molecules
planar
endpoint
point in titration where indicator changes color
strength of dispersion force depends on
polarizability
oxyanions
polyatomic ions containing oxygen
the addition of an electron to a noble gas, however, would require that the electron reside in a higher energy subshell that is empty in the neutral atom. Because occupying a higher energy subshell is energetically unfavorable, the electron affinity is highly ______
positive
chemical energy
potential energy stored in the arrangements of the atoms of the substance
parts per million (ppm)
ppm of component = mass of component in solution/ total mass of solution x 10^6 1 ppm contains one gram of solute for each million grams of solution, or 1 mg of solute per kilogram or liter of solution
If Q > Ksp
precipitation occurs until Q = Ksp
standard atmospheric pressure
pressure sufficient to support a column of mercury 760 mm high
heat of fusion
price at which molecules or ions get more freedom to move- melting process
when electrons are removed from an atom to form a cation, they are always first from the occupied orbitals having the largest
principal quantum number, n
A _______ separates light into its component wavelengths
prism
reaction mechanism
process by which a reaction occurs. Describes in detail the order in which bonds are broken and formed and the changes in relative positions of the atoms during the course of the reaction.
endothermic
process in which system absorbs heat
exothermic
process in which system loses heat
solvation
process that helps stabilize the ions in solution and prevents cations and anions from recombining. because ions and their shells of surrounding water molecules are free to move about, the ions become dispersed uniformly throughout the solution.
colligative properties
properties that depend on the collective effect of the number of solute particles.
enzymes
protein molecules that act as catalysts, increasing rates of biochemical reactions
only the ________ have a bearing on chemical behavior
proton, neutron, and electron
the square of the wave function
provides information about an electron's location when the electron is in an allowed energy state. it does not give us the certain location. but at a given point in space, it represents the probability that the electron will be found at that location. it is called either the probability density or the electron density.
A catalyst lowers the overall activation energy for a chemical reaction usually by
providing a completely different mechanism for the reaction.
delta E =
q (heat added to or removed from the system) + w (work done on or by the system)
E is a state function and _ and _ are not
q and w (they depend on the path system took to its state)
if a rate is 2nd order with respect to a reactant, doubling the concentration of that substance causes the reaction rate to
quadruple. 2^2 = 4
mass percentage
quantitative expression of concentration mass % of component = mass of component in solution / total mass of solution x 100
the electronic charge
quantity of charge of an electron
when solids are heated, they emit...
radiation
monochromatic
radiation composed of a single wavelength
combustion reactions
rapid reactions that produce a flame.
the rate of a reaction depends on concentration, but the ______ does not
rate constant
if we know a reaction is an elementary reaction, then we know its ______
rate law
dynamic equilibrium
rate of exit = rate of enter
one we have the rate law and rate constant for a reaction, we can calculate the ________ for any set of concentrations
rate of reaction
only metals above hydrogen in the activity series can...
react with acids to form H2
m and n in the rate law are called
reaction orders
precipitation reactions
reactions that result in the formation of an insoluble product.
when an atom, ion, or molecule has become more negatively charged, or gained electrons, we say that it is...
reduced
whenever one substance is oxidized, some other substance must be:
reduced
calculated electron density distributions
regions of space that have relatively higher electron density are red. regions of space that have relatively lower electron density are shown in blue. The greater the difference in electronegativity between 2 atoms, the more polar their bond.
differential rate law
relates concentration of A at the start of the reaction, [A]0, to its concentration at any other time t, [A]t.
percent yield
relates the actual yield to the theoretical yield. it equals actual yield / theoretical yield x 100 %
amplitude
relates to the intensity of the radiation. it is the maximum extent of the oscilation of the wave. the measured verticle distance from the midline of the wave to its peak.
particles with the same charge....
repel one another
chemical equations
represent chemical reactions in a concise way
formula units
represented by the chemical formula of the substance, because it is inappropriate to speak of ionic substances as molecules, when they exist as three dimensional arrays of ions. NaCl has the mass of one formula unit: 23 + 35.5 = 58.5 amu.
covalent bond
results from the sharing of electrons between two atoms. generally between nonmetals.
If k >> 1, the equilibrium lies to the
right- products predominate
nonmetal oxides react with bases to form
salts
Cathode Ray experiment
scientists studied electrical discharge through partially evacuated tubed (pumped almost empty of air). high voltage creates radiation within the tube. the radiation originates from the negative electrode, or cathode. the rays could not be seen, but their movement was detected by fluoresce, or the giving off of light by certain materials. the negative plate on the left accelerates electrons to the positive plate at the other end of the tube with a hole in the center. the beam passes through the hole and is deflected by magnetic and electric fields. three paths result in different strengths. the charge to mass ratio was measured by the effects that magnetic and electric fields had on the direction of the beam. Found the ratio of the electron's electrical charge to it's mass.
concentration
scientists use this term to designate the amount of solute dissolved in a given quantity of solvent or quantity of solution.
SI unit for time
second
doubling concentration increases rate by a factor of 2^2 = 4
second order
4 bonding, 1 non bonding electron domain
see saw
chemistry
seeks to understand the properties and behavior of matter through studying the properties and behaviors of atoms and molecules
As n increases, the orbit radius and energy cause the electron to be
separated from the nucleus
selective precipitation
separation of ions in an aqueous solution by using a reagent that forms a precipitate
triple bond
sharing 3 pairs of electrons
double bond
sharing more than one pair of electrons
a fast reaction has a ______ half life
short
high frequency = ____ wavelength
short
ball and stick models
show atoms as spheres and bonds as sticks
Structural formula
shows which atoms are attached to which within the molecule
single bonds are _ bonds
sigma
a double bond consists of one _ bond and one _ bond
sigma, pi
a triple bond consists of one _ bond and two _ bonds
sigma, pi
unimolecular
single molecule is involved
rate determining step
slowest step that limits reaction rate. the rate of a faster step following the rate determining step does not speed up the overall rate.
atoms
small building blocks of matter. Each element is composed of a unique kind of these. they retain the chemical identity of their element.
Oil drop experiment
small drops of oil picked up extra electrons fell between two electrically charged plates. millikan monitored how the voltage affected the rate of their fall. calculated the mass of the electron using the experimental value for the charge and Thompson's charge to mass ratio.
cations are _____ than their parent atoms.
smaller. their formation vacates the most spatially extended occupied orbitals in an atom, decreasing the number of electron-electron repulsions.
If Q < Ksp
solid dissolves until Q = Ksp
melting
solid to liquid
all common ionic compounds of the alkali metal ions and of the ammonium ion are ______ in water
soluble
substances with similar intermolecular attractive forces tend to be _____ in one another
soluble
strong electrolytes
solutes that exist in solution completely or nearly completely as ions. essentially all soluble ionic compounds and a few molecular compounds such as HCl are strong electrolytes.
weak electrolytes
solutes that exist in solution mostly in the form of molecules with only a small fraction in the form of ions.
saturated solution
solution is in contact with undissolved solute
dilution
solutions of lower concentrations being obtained by adding water
supersaturated
solutions that contain a greater amount of solute than that needed to form a saturated solution. for example, when a saturated solution of NaC2H3O2 sodium acetate is made at a high temperature and then slowly cooled, all the solute may remain dissolved even though the solubility decreases as the temperature is reduced.
buffered solutions
solutions that contain a weak conjugate acid-base pair/ can resist drastic changes in pH upon the addition of small amounts of strong acid or strong base.
wave functions
solving Schrodinger's equation leads to a series of mathematical functions that describe the electron. usually represented by the greek symbol psi.
nonmetallic elements, or nonmetals
some are gaseous, some are solid, and one is liquid. they differ from metals in appearance and in other physical properties.
according to the VSEPR theory, a linear arrangement of electron domains implies ___ hybridization
sp
functional groups
specific groups of atoms
radioactivity
spontaneous emission of radiation
processes that are exothermic tend to proceed
spontaneously
4 bonding, 2 non bonding electron domains
square planar
5 bonding, 1 non bonding electron domain
square pyramidal
The effusion rate of a gas is inversely proportional to the
square root of its molar mass. r1/ r2 = square root (M2 /M1) r = rate of effusion M= molar mass (for two substances) this equation compares the rates of effusion of 2 different gases under identical conditions. indicates that the lighter gas effuses more rapidly
the pauli exclusion principle
states that no two electrons in an atom can have the same set of four quantum numbers n, l, ml, and ms. The values n, l, and ml are fixed for a given orbital. Thus, if we want to put more than one electron in an orbital and satisfy this principle, there are two different ms values assigned to the electrons. An orbital can hae a maximum of two electrons and they must have opposite spins.
Raoult's Law
states that the partial pressure exerted by solvent vapor above a solution, Pa, equals the product of the mole fraction of the solvent in the solution, Xa, times the vapor pressure of the pure solvent: Pa = Xa + Poa EXAMPLE H2O has a vapor pressure of 17.5 torr at room temp adding glucose(a nonvolatile solute) to the water changes the mole fraction of water in the solution to 0.800 PH2O = (0.800)(17.5 torr) = 14.0 torr
Strong electrolytes
strong acids and bases are these. They exist in aqueous solution entirely as ions.
acids and bases that are strong electrolytes (completely ionized in solution) are...
strong acids and strong bases
soluble ionic compounds are...
strong electrolytes. ionic compound contain the ammonium ion or metals and nonmetals
The greater the stability of the conjugate base, X-, the _____ the acid
stronger
more polar molecules have the ____ attractions
stronger
The position of the equilibrium favors the reaction of the stronger....
stronger acid and stronger base to form the weaker acid and the weaker base.
substances made up of the more massive molecule have the
strongest attractions
Gold Foil experiment
studied the angles at which alpha particles were deflected, or scattered, as they passed through a thin gold foil a few thousand atoms thick. All the alpha particles passed through the foil without deflection, except for a small amount of the scattering observed at large angles (almost back to their source) and slight deflections.
physical changes
substance changes its physical appearance but not its composition
chemical changes/ chemical reaction
substance is transformed into a chemically different substance
homogeneous equilibria
substances all in the same phase
heterogeneous equilibria
substances in different phases
components
substances making up a mixture
negligible acidity
substances such as CH4 that contain hydrogen but do not demonstrate any acidic behavior in water. Their conjugate bases are strong bases, reacting completely with water, abstracting protons to form OH- ions.
bases
substances that accept (react with) H+ ions
amines
substances that include ammonia and a related class of compounds. one or more of the N-H bonds is replaced with N-CH3. They can abstract a proton from a water molecule by forming an additional N-H bond.
acids
substances that ionize in aqueous solutions to form hydrogen ions, thereby increasing the concentration of H+ (aq) ions. Hydrogen atom consists of a proton and an electron...H+ is simply a proton > acids are also called proton donors.
substrates
substances that undergo reaction at the active site
heat of sublimation
sum of the heats of vaporization and fusion.
overall reaction order
sum of the orders with respect to each reactant in the rate law
bond angles deviate from the ideal angles when
surrounding atoms and electron domains are not identical.
closed systems
systems we can most readily study -can exchange energy but not matter with its surroundings -exchanges energy with its surroundings in the form of heat and work
half life
t1/2 is the time required for the concentration of a reactant to reach one half of its initial value, [A]t1/2 = 1/2[A]0
a gas composed of light particles, such as He, will have the same average kinetic energy as one composed of heavier particles, such as Xe, if the 2 gases are at the same
temperature
thermal energy
temperature
vapor pressure increases nonlinearly with increasing
temperature
the rate constant is affected by (2 things)
temperature and the presence of a catalyst
freezing point of a solution
temperature at which the first crystals of pure solvent begin to form in equilibrium with solution.
metals tend to have low ionization energies and therefore
tend to form positive ions relatively easily.
hypothesis
tentative explanation that guides us in planning further experiments
four electron domains are arranged
tetrahedrally
quantum mechanics
the "new" physics that had to be developed to describe atoms correctly
lanthanide elements, or rare earth elements
the 14 elements corresponding to the filling of the 4f orbitals
kelvin scale
the SI temperature scale, and the SI unit of temperature is K for Kelvins
electronegativity
the ability of an atom in a molecule to attract electrons to itself. related to the ionization energy and electron affinity, which are properties of isolated atoms. ionization energy- how strongly an atom holds onto its electrons. electron affinity- how strongly an atom attracts additional electrons.
according to the Arrhenius equation, the rate constant k is determined by
the activation energy Ea and the frequency factor A.
oxidation number
the actual charge for a monatomic ion. each atom in a neutral molecule or charged species is assigned an oxidation number. the oxidation number is the hypothetical charge assigned to the atom, assuming that the electrons are completely held by one atom or the other. the number changes in a redox reaction.
calorie
the amount of energy required to raise the temperature of 1 g of water from 14.5 degrees C to 15.5 degrees C.
Density
the amount of mass in a unit volume of a substance
actual yield
the amount of product actually obtained in a reaction. Almost always less than the theoretical yield and is never greater than the theoretical yield. This is because part of the reactants may not react, or they may react in a way different from that desired. Also, it is not always possible to recover all of the product from the reaction mixture.
entropy
the amount of randomness or disorder in a system
the solubility of a substance
the amount of solute (that substance) that is needed to form a saturated solution in a given quantity of solvent (another substance). expressed as g/L. represents the maximum amount of that substance that can be dissolved in the solvent to give a stable equilibrium solution at a given temperature
solubility
the amount of that substance that can be dissolved in a given quantity of solvent at that temperature.
bond angle
the angles made by the lines joining the nuclei of the atoms in the molecule.
chemical kinetics
the area of chemistry that is concerned with the speeds, or rates of reactions
stoichiometry
the area of study that examines the quantities of substances consumed and produced in chemical reactions.
electron domain geometry
the arrangement of electron domains about the central atom of an ABn molecule or ion.
the periodic table
the arrangement of elements in order of increasing atomic number, with elements having similar properties placed in vertical columns.
molecular geometry
the arrangement of only the atoms in a molecule or ion--nonbonding pairs are not part of it.
structure
the arrangement of these atoms
either increasing the effective nuclear charge or decreasing the distance from the nucleus increases
the attraction between the electron and the nucleus.
solutions form when:
the attractive forces between solute and solvent particles are comparable in magnitude with those that exist between the solute particles themselves or between the solvent particles themselves.
atomic weight
the average atomic mass of each element (expressed in amu) they are listed in the periodic table
mean free path
the average distance traveled by a molecule between collisions. high pressure = short mean free path low pressure = long mean free path
the state of a substance depends on?
the balance between the kinetic energies of the particles and the interparticle energies of attraction. the kinetic energies depend on temperature: keep particles apart and moving. the interparticle energies of attraction draw the particles together. there are weak interparticle energies in gases and strong ones in solids.
basis of the VSEPR model
the best arrangement of a given number of electron domains is the one that minimizes the repulsions among them.
enzyme-substrate complex
the combination of the enzyme and the substrate bonding between them involves IMFs like dipole-dipole attractions, hydrogen bonds, and London Dispersion forces
corrosion
the conversion of a metal into a metal compound by a reaction between the metal and substance in the environment. rusting involves the reaction of oxygen with iron in the presence of oxygen. when a metal corrodes, it loses electrons and forms cations.
chromatography
the different abilities of substances to adhere to the surfaces of various solids such as paper and starch is used to separate mixture.
law of constant composition / law of definite proportions
the elemental composition of a pure compound is always the same. chemists and nature use the same elements and natural laws, so there is no difference between compounds composed in the lab and the corresponding compounds found in nature. In a given compound, the relative numbers and kinds of atoms are constant.
the photoelectric effect
the emission of electrons from metal surfaces on which light shines
emission spectra
the emission of light from electronically excited gas atoms
blackbody radiation
the emission of light from hot objects. the objects study appear black before heating
electron affinity
the energy change that occurs when an electron is added to a gaseous atom. It measures the affinity, or attraction, of the atom for the added electron.
the barrier of activation energy represents
the energy necessary to force the molecule through the relatively unstable intermediate state to the final product.
kinetic energy
the energy of motion KE = 1/2mv^2
adsorption
the initial step in heterogeneous catalysis refers to binding of molecules to a surface, whereas absorption refers to the uptake of molecules into the interior of another substance. -occurs because the atoms or ions at the surface of a solid are extremely reactive.
shielding
the inner core electrons partially shield or screen the outer electrons from the attraction of the nucleus.
If Ka is greater than Kb,
the ion will cause the solution to be acidic.
composition
the kinds of atoms matter contains
density vs weight
the less dense will float over the dense
electromagnetic radiation
the light that we can see with our eyes, visible light. 1. carries energy through space--also known as radiant energy 2. many types in addition to visible light 3. all share certain fundamental characteristics
ground state
the lowest energy state, n=1, is called the _____ of the atom
molar mass
the mass in grams of one mole of a substance
1 mol of an element is equal to:
the mass of a single atom of an element (in amu) equals 1 mol of that element (in grams)
calorimetry
the measurement of heat flow
activation energy
the minimum energy required to initiate a chemical reaction, Ea, which varies from reaction to reaction
ionization energy
the minimum energy required to remove an electron from the ground state of the isolated gaseous atom or ion. the first ionization energy is the energy needed to remove the first electron from a neutral atom. the second ionization energy is the energy needed to remove the second electron.
molality is the concentration unit of choice when a solution is to be used over a range of temperatures because
the molality of a solution does not vary with temperature because masses do not vary with temperature.
the decrease in freezing point of a solution in comparison to the freezing point of the pure liquid is proportional to
the molality of the solute. deltaTf = Kfm Kf = molal freezing point depression constant
the intramolecular forces within molecules that give rise to covalent bonding influence what aspects of chemical behavior?
the molecular shape, bond energies
why do collisions make diffusion more complicated?
the molecular speeds are high, but the diffusion of gases is slow. This happens because real gas molecules have finite volumes.
London dispersion forces
the motion of an electron in an atom or molecule can create an instantaneous dipole moment. temporary dipole on one atom can induce a similar temporary dipole on an adjacent atom, causing atoms to be attracted. significant only when molecules are very close together.
above the critical temp...
the motional energies of the molecules are greater than the attractive forces that lead to the liquid state regardless of how much the substance is compressed to bring the molecules closer together.
electron affinity > 0 indicates that
the negative ion is higher in energy than the separated atom and electron.
pH is ?
the negative log base 10 of [H+]
osmosis
the net movement of solvent is always toward the solution with the higher solute concentration
frequency
the number of complete wavelengths, or cycles, that pass a given point each second.
when solvent is added to dilute a solution...
the number of moles of solute remains unchanged
atomic number
the number of protons in the nucleus of an atom of any particular element. all atoms of a given element have the same atomic number.
coefficients
the numbers in front of the formulas. They indicate the relative numbers of molecules of each kind involved in the reaction.
excess reactants
the other reactants besides the limiting
equivalence point ?
the point at which stoichiometrically equivalent quantities of acid and base have been brought together.
dipole moment
the quantitative measure of the magnitude of a dipole. Denoted mu.
theoretical yield
the quantity of product that is calculated to form when all of the limiting reactant reacts
instantaneous rate
the rate at a particular moment in the reaction (slope of tangents on the graph)
Graham's Law
the ratio of rates of diffusion of two gases under identical experimental conditions r1 / r2 = square root (M2/ M1)
the activity of any substance in an ideal mixture is
the ratio of the concentration of the substance in molarity to a standard concentration of 1 M or, if the substance is a gas, the ratio of the partial pressure in atmospheres to a standard pressure of 1 atm.
limiting reactant
the reactant that is completely consumed in a reaction. It determines, or limits, the amount of product formed.
the orientation factor
the relative orientations of the molecules during their collisions determine whether the atoms are suitably positioned to form new bonds
Viscosity
the resistance of a liquid to flow depends on attractive forces between molecules and structural features that cause the molecules to become entangled.
multiplication and division with significant figures
the result contains the same number of significant figures as the measurement with the fewest significant figures
adding and subtracting with significant figures
the result has the same number of decimal places as the measurement with the fewest decimal places.
radial probability function
the resulting curve when we plot the radial probability density for the orbital as a function of r, the distance from the nucleus.
capillary action
the rise of liquids up very narrow tubes 1. adhesive forces increase surface area of the liquid 2. surface tension reduces the area, pulling the liquid up the tube.
representative elements/ main group elements
the s block and the p block of the periodic table together.
subshell
the set of orbitals that have the same n and l values
root-mean-square speed, u
the speed of a molecule possessing average kinetic energy. The different between rms and average speed is small. E (avg kinetic energy) = 1/2mu^2 m = mass of molecule u = rms speed
diffusion
the spread of one substance throughout a space or throughout a second substance
Coulomb's law
the strength of the interaction between two electrical charges depends on the signs and magnitudes of the charges and on the distance between them. the force of attraction between an electron and the nucleus depends on the magnitude of the net nuclear charge acting on the electron and on the average distance between the nucleus and the electron.
organic chemistry
the study of compounds of carbon
quantitative significance
the subscripts in formulas and the coefficients in equations represent precise quantities. chemical formulas and equations both have this significance.
solvent
the substance present in the greatest quantity
formula weight
the sum of the atomic weights of each atom in its chemical formula. For example, H2SO4 is 98.1 amu.
chemical nomenclature
the system used in naming substances.
periodic table
the table in which symbol for each element is enclosed in a box. the elements are arranged in vertical columns so that closely related elements are grouped together.
normal boiling point
the temperature at which a liquid's vapor pressure equals 1 atm.
transition elements/ transition metals
the ten elements in the fourth row of the periodic table. 3d orbitals
law of conservation of mass/ matter
the total mass of materials present after a chemical reaction is the same as the total mass present before the reaction.
mass number
the total number of protons plus neutrons in the atom
While studying properties of air, John Dalton observed that
the total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone.
mole
the unit for dealing with the number of atoms, ions, or molecules in a common-sized sample.
the metric system
the units used for scientific measurements
triple point
the vapor pressure curves for the liquid and solid phases meet at this point
electromagnetic spectrum
the various types of electromagnetic radiation arranged in order of increasing wavelength.
groups
the vertical columns of the periodic table
Boyle's Law
the volume of a fixed quantity of gas maintained at constant temperature is inversely proportional to the pressure V = constant x 1/p or PV = constant constant depends on temp. and amount of gas in the sample.
Charles's Law
the volume of a fixed quantity of gas(at constant pressure) increases linearly with temperature. The volume of a fixed amount of gas maintained at constant pressure is directly proportional to its absolute temperature V = constant x T or V/T = constant constant depends on pressure and amount of gas
Avogadro's law
the volume of a gas maintained at constant temperature and pressure is directly proportional to the number of moles of a gas V = constant x n
electron configuration
the way in which the electrons are distributed among the various orbitals of an atom. because of the pauli exclusion principle, orbitals are filled in order of increasing energy, with no more than two electrons per orbital.
pure solids and liquids are excluded from the equilibrium expression because?
their activity equals 1
if every ion in a complete ionic equation is a spectator...
then no reaction occurs.
molecular compounds that are gases have low molar masses because?
they are composed entirely of nonmetallic elements and have simple molecular formulas
vector quantities
they have magnitude and direction. bond dipoles and dipole moments are vectors.
because electron domains are negatively charged
they repel one another
inexact numbers
those whose values have some uncertainty- numbers obtained by measurement- there is equipment and human error
titration
to determine the concentration of a particular solute in a solution. chemists combine a sample of the solution with a reagent solution of known concentration, called a standard solution.
hybrid orbitals
to explain molecular geometries, we often assume that the atomic orbitals on an atom mix to form new orbitals called ______
electron transfer
to form oppositely charged ions. occurs when one of the atoms readily gives up an electron (low ionization energy) and the other atom readily gains an electron (high electron affinity).
strong acids
transfer their protons to water, leaving no undissociated molecules in solution. their conjugate bases tend to be protonated- abstract protons in aqueous solution.
five electron domains are arranged
trigonal bipyramidal
three electron domains are arranged in a
trigonal planar fashion
AB3
trigonal planar, trigonal pyramidal, or T shaped
acid base indicator
turns one color in an acid and another in a base. If you know the pH at which the indicator changes color, you can determine if a solution has a higher or lower pH than this value.
overlap
two electrons of opposite spin share common space between the nuclei, forming a covalent bond.
allotropes
two forms of the same element in the same state
equillibrium
two opposing processes occur at equal rates
polyatomic ions description
two or more atoms are bound together by predominantly covalent bonds, they form a stable grouping that carries a charge, either positive or negative. the group of atoms as a whole acts as a charged species when the ion forms an ionic compound with an ion of opposite charge.
molecular form
two or more of the same type of atom are bound together
combination reaction
two or more substances react to form one product. an example of this is when elements combine to form compounds.
pi bonds can form only if
unhybridized p orbitals are present on the bonded atoms. only atoms having sp or sp2 hybridization can be involved in such pi bonding.
properties of ionic substances
usually brittle with high melting points. usually crystalline: solids have flat surfaces that make characteristic angles with one another. can break apart along smooth, flat surfaces. these characteristics result from electrostatic forces that keep ions in rigid, well defines 3d arrangement.
R = gas constant
value and units depend on P, V, n and T. T must always be absolute (Kelvins) n is normally expressed in moles P and V most often atm and liters
many metals can be oxidized by aqueous solutions of....
various salts
properties of nonmetals
vary greatly in appearance they are not lustrous poor conductors of heat and electricity melting points are generally lower than those of metals
heterogeneous
vary in texture and appearance throughout any typical sample
liquids that evaporate readily are
volatile
Derived SI unit
volume and density
22.4 L
volume occupied by one mole of ideal gas at STP.
molarity is a conversion factor between:
volume of solution and moles of solute
gas expands
w is negative --> energy leaves system
gas compressed
w is positive --> energy enters the system
A neutralization reaction between an acid and a metal hydroxide produces
water and a salt
to verify the purity of a compound:
we compare the calculated percentage composition of the substance with that found experimentally.
If HX is a weak acid, the conjugate base of X- is a _____ base. this anion will react with water to a _____ extent to produce the weak acid and the hydroxide ions
weak small extent
acids and bases that are weak electrolytes (partly ionized in solution) are...
weak acids and weak bases
the stronger a base, the ________ its conjugate acid
weaker
the stronger an acid, the _______ its conjugate base
weaker
balanced equations
when a chemical equation has an equal number of atoms of each element on each side of the arrow.
neutralization reaction
when a solution of an acid and a solution of a base are mixed H+ ions and OH- ions come together to form H2O molecules
spectrum
when radiation from many sources produce radiation containing many different wavelengths, and radiation from such sources is separated into its different wavelength components, this is produced.
excited state
when the electron is in higher energy, or less negative orbit--n=2 or higher, then the atom is said to be in an ____ state
displacement reactions
when the ion in solution is displaced or replaced through oxidation of an element. A + BX > AX + B
dynamic equilibrium
when the rates of the opposing processes of dissolving and crystallizing of solutes in a solvent become equal
hydration
when the solvent is water, and ions are surrounded by water molecules.
chemical bond
whenever two atoms or ions are strongly attracted to each other. There are 3 types: ionic, covalent, metallic
pressure volume work
work involved in the expansion or compression of gases w = -PdeltaV
sodium gives a _____ colored flame
yellow
monoprotic acids
yield one H+ per molecule of acid. Examples: HCl and HNO3
Kp = Kc when change in n =
zero
concentration of reactant has no effect on the rate = _______ order
zero order
units of frequency
"per second" s^-1, or /s
Thompson's model of the atom
"plum pudding model" consisted of uniform positive sphere in which electrons were embedded.
molecularity
# of molecules that participate as reactants in an elementary reaction.
the calculation of percent composition:
% element = (number of atoms of that element x atomic weight of that element) / formula weight of the compound x 100
For the equation aA + bB ----> cC + dD, the rate =
( means multiply* -1/a(change in [A]/t) = -1/b(change in [B]/t) = 1/c(change in [C]/t) = 1/d(change in [D]/t)
charge of a proton
+1.602 x 10 ^ -19 C
charge of an electron
-1.602 x 10 ^ -19 C
the collision model
-based on kinetic molecular theory -accounts for effects of concentration and temperature on rate @ molecular level -central idea: molecules must collide to react -greater # of collisions per second = greater reaction rate -greater concentration > more collisions > greater rate -higher temp > faster molecular speed > more collisions > greater rate -only a tiny fraction of collisions lead to a reaction
pKa =
-logKa
pKb =
-logKb
-log[H+] + (-log[OH-]) =
-logKw
conditions of standard temperature and pressure
0 degrees Celsius and 1 atm. Many properties of gases tabulated for these conditions.
t1/2 for a first order rate law does not depend on the starting concentration, so t1/2 =
0.693/k
the sum of all mole fractions of all components of a solution must equal
1
units for pressure
1 atm = 760 mmHg = 760 torr = 1.01325 x 10^5 Pa = 101.325 kPa
1 J =
1 kg-m^2 / s^2
factors involved in processes that occur spontaneously:
1. processes in which the energy content of the system decreases tend to occur spontaneously (ex- ball dropping- potential energy- kinetic energy- heat energy) 2. more dispersed state of one or more components, resulting in an overall increase in the randomness of the system. (distribution of each component into a larger volume)
the overall enthalpy change (energetics) in forming a new solution is the sum of three components:
1. separation of the solute particles from one another requires an input of energy to overcome their attractive interactions (endothermic - input of energy) 2. separation of solvent molecules also requires energy. 3. the attractive interactions between solute and solvent (exothermic- output of energy)
four variables are needed to define the physical condition, or state, of a gas:
1. temperature, T 2. pressure, P 3. volume, V 4. amount of gas, number of moles, n
according to the kinetic molecular theory, the average kinetic energy of any collection of gas molecules =
1/2 mu^2 and has a specific value at a given temperature
integrated rate law for a second order reaction
1/[A]t = kt + 1/[A]0
At lower pressures (<__ atm) the deviation from ideal behavior is small and we can use the ideal gas equation without generating serious error.
10
one angstrom equals ____ m
10 ^ -10 m
What is the atmospheric pressure at sea level?
100 kPa = 1 bar
tetrahedral
109.5 degrees
What is a bar unit?
10^5 pascals
each equatorial domain in the trigonal bipyramidal electron domain geometry makes a ___ degree angle with either of the other two equatorial domains
120
trigonal planar bond angle
120 degrees
pH + pOH =
14.00 at 25 degrees C
linear bond angle
180 degrees
how many centimeters in an inch?
2.54 cm = 1 in.
normal room temperature
25 degrees
each subshell consists of a specific number of orbitals. for a given value of l, there are ____ orbitals
2l +1
each shell can accommodate up to ____ electrons
2n^2
beginning with the n= 2 shell, each shell has ____ p orbitals
3
Groups 5, 6, 7 elements will contain anions with charges
3-, 2- 1-
wavelengths of visible light
4 x 10^-7 to 7 x 10^-7 m
1 calorie = ___ J
4.184 J
each axial domain in the trigonal bipyramidal electron domain geometry makes a ____ degree angle with an equatorial domain
90
trigonal bipyramidal
90 degrees, 120 degrees
octahedral
90 degrees, 90 degrees
pOH
=-log[OH-]
termolecular rate law
A + A+ A ---> products Rate = k[A]^3 A + A + B ---> products Rate = k[A]^2[B] A+B+C---> products Rate = k[A][B][C]
bimolecular rate law
A +B ---> products Rate = k [A][B] A + A ----> products Rate = k [A]^2
unimolecular rate law
A ---> products Rate = k[A]
A metal combines with a nonmetal to form
A binary salt
why is the electron domain of a nonbonding pair more spread out in space?
A bonding pair of electrons is attracted by both nuclei of the bonded atoms. A nonbonding pair is attracted primarily by one nucleus. Because a nonbonding pair experiences less nuclear attraction, its electron domain is more spread out in space than the electron domain for a bonding pair. electron domains for nonbonding electron pairs exert greater repulsive forces on adjacent electron domains and tend to compress the bond angles.
the frequency factor
A in the Arrhenius equation. It is a constant, as temperature is varied. -related to the frequency of collisions and the probability that the collisions are favorably oriented for reaction -reaction rates decrease as Ea increases(molecules that possess required energy is smaller fraction)
Nonmetallic oxides and water form
Acids (the nonmetal retains it's oxidation number)
The Arrhenius concept of acids and bases
Acids are substances that, when dissolved in water, increase the concentration of H+ ions. Bases are substances that, when dissolved in water, increase the concentration of OH- ions. -restricted to aqueous solution
Bohr's model of the atom
After Rutherford discovered the nucleus, to explain the line spectrum of hydrogen, Bohr started by assuming that electrons move in circular orbits around the nucleus. 3 postulates: 1. Only orbits of certain radii, corresponding to certain definite energies, are permitted for the electron in a hydrogen atom. 2. An electron in a permitted orbit has a specific energy and is in an "allowed" energy state. An electron in an allowed energy state will not radiate energy and therefore will not spiral into the nucleus. 3. energy is emitted or absorbed by the electron only as the electron changes from one allowed energy state to another. This energy is emitted or absorbed as a photon, E=hv.
Group 1
Alkali metals
Group 2
Alkaline earth metals
G.N. Lewis
American chemist who suggest the simple way of tracking/ showing valence electrons during the course of bond formation.
Ammonium hydroxide decomposes into
Ammonia and water
Ammonium carbonate decomposes into
Ammonia, water, and carbon dioxide
SI unit for electric current
Ampere - A
salts of a strong acid + a weak base will hydrolyze to give
An acidic solution
Salts of a weak acid + a weak base hydrolyze to give
An acidic, basic, or neutral solution.
X Ray
Angstrom- 10^-10 m
Metallic oxides and water form
Bases (metallic hydroxides
Salts of a weak acid + strong base will hydrolyze to give a
Basic solution
Why is the condition of zero volume at -273 degrees Celsius never realized?
Because gases liquefy or solidify before reaching this temperature.
Why do multiple bonds also represent larger electron domains?
Because multiple bonds contain a higher electron charge density than single bonds.
P1V1 = P2V2
Because the product PV is a constant when a gas is held at constant n and T, we know this is true. 1 = initial values 2= final values
Why do the values for a given element's ionization energies increase as successive electrons are removed?
Because with each successive removal, an electron is being pulled away from an increasingly more positive ion, requiring increasingly more energy.
the dipole moment from HF to HI decreases even though the bond length increases? Why?
Because, for these molecules, the decrease in electronegativity difference has a greater effect on the dipole moment than does the change in bond length.
carboxyl group
COOH
SI unit for luminous intensity
Candela - cd
JJ. Thompson's experiment
Cathode ray experiment
Microwave
Centimeter- 10^-2 m
Group 16
Chalcogens
Evidence of a chemical change
Color change, bubbles form(gas produced), temperature change, substance disappears, solid formed, new odor produced
whether an anion reacts with water to produce hydroxide depends on the strength of the
Conjugate acid.
Density has units of mass per volume
D = m/v
matter waves
De Broglie used this term to describe the wave characteristics of material particles.
The line that separates metals from nonmetals
Diagonal step like line that runs from Boron, B, to Astantine, At
Acids ionize in water, bases...
Dissociate
Salts of a strong acid + a strong base...
Do not undergo hydrolysis. Their aqueous solutions are always neutral
Why can we relate the amount of a given gas in a mixture to its partial pressure?
Each gas behaves independently
Derivation of the Ideal Gas Equation
Each gas law was obtained by holding two variables constant in order to see how the remaining two variables affect eachother. Boyle's Law: V is proportional to 1/P (constant n, T) Charles's Law: V is proportional to T (constant n, P) Avogadro's Law: V is proportional to n (constant P, T) We can combine these for a general gas law: V is proportional to nT/P If we call the proportionality constant R, we obtain: V = R(nT/P) rearranged ---> PV = nRT
How did Einstein explain the photoelectric effect?
Einstein assumed that the radiant energy striking the metal surface is behaving not like a wave but rather as if it were a stream of tiny energy packets. Each energy packet, called a photon, behaves like a tiny particle.
the photoelectric effect
Einstein used Planck's quantum theory to explain this effect, 1. when photons of sufficiently high energy strike a metal surface, electrons are emitted from the metal. 2. light shining on a clean metal surface causes the surface to emit electrons. 3. for each meal, there is a minimum frequency of light below which no electrons are emitted.
Avogadro's Hypothesis
Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules
To convert Celsius into Fahrenheit
F = 9/5(C) + 32
What are the highest and lowest electronegativities in the periodic table?
Fluorine has an electronegativity of 4.0 (most). Cesium has an electronegativity of 0.7 (least).
Rutherford's experiment
Gold Foil experiment
hydride ion
H atom that has gained an electron, H-.
hydronium ion
H+ + H2O ---> H3O+. Can form hydrogen bonds to additional H2O molecules to generate larger clusters of hydrated hydrogen ions, such as H5O2+ and H9O4+ Chemists use H+ and H3O+ to represent the hydrated proton that is responsible for the characteristic properties of aqueous solutions of acids
hydrogen ion
H+, formed when hydrogen atom loses its electron.
Group 17
Halogens
the relationship between pressure and the solubility of a gas is expressed by
Henry's law
the 7 diatomic elements
Hydrogen, Oxygen, Nitrogen, Fluorine, Chloride, Bromine, Iodine
adhesive forces
IMFs that bind a substance to a surface
cohesive forces
IMFs that bind similar molecules to one another
Le Chatlier's Principle
If a system at equilibrium is disturbed by a change in temperature, pressure, or the concentration of one of the components, the system will shift its equilibrium position so as to counteract the effect of the disturbance.
Effect of a temperature increase at constant volume
Increasing temp = increase in avg kinetic energy = increase in rms speed u. no change in volume = more collisions change in momentum in each collision increases (molecules strike walls more forcefully) model explains pressure increase
To convert Celsius into Kelvins
K= C + 273.15
base dissociation constant
Kb. The constant always refers to the equilibrium in which a base reacts with H2O to form the corresponding conjugate acid and OH-.
equilibrium constant expression
Kc = [D]^d[E]^e / [A]^a[B]^b
Equilibrium expression in terms of pressure
Kp = (PD)^d(PE)^e / (PA)^a (PB)^b
How to calculate Kp from Kc
Kp = Kc(RT) ^ change in n change in n = moles of gaseous product - moles of gaseous reactant
solubility product constant
Ksp, written with same rules as the equilibrium expression. It equals the product of the concentration of the ions involved in the equilibrium, each raised to the power of its coefficient in the equilibrium equation.
Ka x Kb =
Kw, 1.0 x 10^-14
to solve for molar mass of a gas:
M= dRT / P
to calculate the number of moles solute in dilute solution:
Mconc x Vconc = Mdil x Vdil M1 x V1 = M2 x V2
Metallic chlorates decompose into
Metallic chlorides and oxygen
Metallic carbonates decompose into
Metallic oxides and carbon dioxide
TV, radio waves
Meter- 1m
Infared
Micrometer- 10^-6 m
Infared 2
Millimeter- 10^-3 m
SI unit for the amount of a substance
Mole
Rutherford's explanation
Most of the mass of each gold atom in his foil and all of its positive charge reside in a small, extremely dense region, called the nucleus. the alpha particles that came close to a positively charged gold nucleus are the one who were deflected.
SI unit for pressure is?
N/m^2 = Pascal (Pa)
elements that exist as gases under ordinary conditions of temperature and pressure
N2 and O2 (air) H2, F2, Cl2 He, Ne, Ar, Kr, Xe (the noble gases)
Ultraviolet, visible
Nanometer- 10^-9 m
will additional solute dissolve if added to a saturated solution?
No
Group 18
Noble Gases
superoxide
O2 -
peroxide
O2 2-
ozone
O3
absolute temperature scale
On the Kelvin scale, 0 K = -273.15 degrees celsius
alcohols
Organic compounds that contain the OH group attached to a C atom
Collecting gases over water. P total =
P gas + P H2O total pressure = pressure of gas collected + pressure of water vapor in equilibrium with liquid water.
P1 / Pt = (n1RT/ V) / (ntRT / V) = n1 / nt ---> rearrange
P1 = (n1/nt)Pt = X1Pt X = mole fraction- ratio n1 / nt
How to find an element's partial pressure
P1 = n (RT/ V) P2 = n (RT/V) ...
Because n is constant, and P, V, and T can all change for a fixed number of moles of a gas...
PV/ T = nR = constant P1V1 / T1 = P2V2 / T2
the extent to which a real gas departs from ideal behavior can be seen by rearranging the ideal gas equation to solve for n:
PV/RT = n n =1 for ideal gases
the rate of effusion is directly proportional to the rms speed of the molecules because
R and T are constant. u = square root (3 RT/ M) = square root (3 RT/M1 / 3RT/M2) = square root (M2 / M1) r1 / r2 = u1 / u2
an ideal gas obeys the ideal gas equation and an ideal solution obeys
Raoult's Law
to find the extent of the decrease in the vapor pressure of a solvent upon addition of the solute
Raoult's Law
Rate Law
Rate = k[A]^m[B]^n
Zeff = Z - S
S is a positive number called the screening constant. It represents the portion of the nuclear charge that is screened from the valence electron by the other electrons in the atom. EX.) Sodium has a nuclear charge of 11+ (atomic number) The inner core is 10 electrons. We expect the valence electrons of the Na atom to experience an effective nuclear charge 11-10= 1+
joule
SI unit for energy (J)
units of rate constant for a first order rate law
S^-1
Metallic oxides and nonmetallic oxides form
Salts
Henry's Law
Sg = kPg Sg = solubility of the gas in the solution phase (usually expressed as molarity) Pg = the partial pressure of the gas over the solution K = a proportionality constant known as Henry's law constant
Most common strong acids
Six monoprotic acids HCl HClO3 HClO4 HBr HI HNO3 one diprotic acid: H2SO4
The only substances that should be written as ions in ionic equations are
Soluble salts, strong acids, strong bases
Bronsted Lowry Acid
Substance (molecule or ion) that can donate a proton to another substance
Bronsted Lowry Base
Substance that can accept a proton
Sulfurous acid decomposes into
Sulfur dioxide and water
3 bonding, 2 nonbonding electron domains
T shaped
why does the phase diagram of a solution and hence its boiling and freezing points differ from that of the pure solvent?
The addition of a nonvolatile solute to the pure solvent lowers the vapor pressure of the solution.
If Q >K
The concentration of products is too large and that of reactants too small. Thus, substances on the right side of the chemical equation will react to form substances on the left; the reaction moves from right to left in approaching equilibrium
If Q <K
The concentration of products is too small and that of reactants too large, thus, the reaction will achieve equilibrium by forming more products; it moves from left to right.
How can we get a sense of the magnitude of Zeff for an electron in an atom?
The electron density that is due to the inner core of electrons that are attracted to the nucleus is partially effective at partially cancelling the attraction of the valence electron to the nucleus.
If Q =K,
The system is at equilibrium
the Heisenberg uncertainty principle
This principle states that it is inherently impossible for us to know simultaneously both the exact momentum of the electron and its exact location in space.
A binary compound may break down into
Two elements
C = (speed of light equation)
V(lamda) V= frequency- cycles per second- Hz- hertz lamda (upside down V- greek letter) - wavelength- units of length C= speed of light
Hydrogen peroxide decomposes into
Water and oxygen
How can we calculate the volumes of gases formed or consumed in chemical reactions?
We can use the ideal gas equation to define the relationship between the density of a gas and its molar mass
effective nuclear charge, Zeff
We can view the net electric field as it results from a single positive charge located at the nucleus. This charge is smaller than the actual nuclear charge because it also accounts for the repulsion of the electron by other electrons in the atom.
How to predict shapes of ABn molecules
When A is a representative element (s or p block) we can answer this using the VSEPR method.
Kw the ion product constant
[H3O+][OH-] = 1.0 x 10^-14 @ 25 degrees C
homogenous catalyst
a catalyst that is present in the same phase as the reacting molecules.
work function
a certain amount of energy that is required for an electron to overcome the attractive forces that hold it in the metal. A photon can strike a metal surface, be absorbed, and transfer its energy to an electron in the metal. Photons of radiation impinging on the metal must have more energy than the work function for electrons in the metal to quire sufficient energy to escape from the metal surface. Excess energy appears as the kinetic energy of the emitted electrons
ion
a charged particle that is formed if electrons are removed from or added to a neutral atom
SI units
a choice of metric units specified for use in scientific measurements
ionic compound
a compound that contains both positively and negatively charged ions.
the energy, E, of a single quantum/photon equals
a constant times the frequency of the radiation. E = hV
when a weak electrolyte ionizes in solution, the reaction is written with...
a double arrow. there is a balance between opposing processes: molecules ionizing and ions recombining.
conversion factor
a fraction whose numerator and denominator are the same quantity expressed in different units. the denominator is the given unit, and the numerator is the desired unit. the denominator cancels the given unit in the data and the numerator give the unit to the final answer.
tetrahedron
a geometric object with four corners and four faces, each of which is an equilateral triangle.
pH titration curve
a graph of the pH as a function of the volume of the added titrant
heating curve
a graph of the temperature of the system versus the amount of heat added because melting and vaporizing are endothermic processes, the temperature remains constant. phase change = plateau. deltaHfus or deltaHvap
phase diagram
a graphical way to summarize the conditions under which equillibria exist between the different states of matter.
solution
a homogenous mixture of two or more substance
precision
a measure of how closely individual measurements agree with one anther
lattice energy
a measure of how much stabilization results from arranging oppositely charged ions in an ionic solid. The energy required to completely separate a mole of solid ionic compound into its gaseous ions.
the absolute temperature of a gas is
a measure of the average kinetic energy of molecules. molecular motion increases with increasing temperature.
surface tension
a measure of the inward forces that must be overcome in order to expand the surface area of a liquid. the energy required to increase the surface area of a liquid by a unit amount.
equilibrium state
a mixture in which the concentrations of reactants and products no longer change with time.
kinetic molecular theory
a model that helps us understand the physical properties of gases and picture what happens to gas particles as experimental conditions such as temperature and pressure change. 1. gases consist of large numbers of molecules that are in continuous, random motion. 2. the combined volume of all the molecules of the gas is negligible relative to the total volume in which the gas is contained. 3. attractive and repulsive forces between gas molecules are negligible. 4. Energy can be transferred between molecules during collisions, but the average kinetic energy of the molecules does not change with time, as long as the temperature of the gas remains constant. In other words, the collisions are perfectly elastic. 5. The average kinetic energy of the molecules is proportional to the absolute temperature. At any given temperature the molecules of all gases have the same average kinetic energy.
diatomic molecule
a molecule that is made up of two atoms
dispersion forces dominate when...
a nonpolar substance like C6H14 dissolves in another nonpolar one like CCl4
saturated
a solution that is in equilibrium with undissolved solute
hydrogen bond
a special type of attraction between the H atom in a polar bond (particularly an H-F, H-O, or H-N bond) and an unshared electron pair on a nearby small electronegative ion or atom. (usually an F, O, or N atom in another molecule). 1. positive end of bond dipole has the concentrated charge of the partially exposed, bare proton of the hydrogen nucleus. 2. positive charge attracted to the negative charge of an electronegative atom in nearby molecule. 3. H atom is small and can approach electronegative atom closely and interact strongly with it. ice is less dense than liquid water because of hydrogen bonding ice- ordered arrangement of H2O with cavities water- structure collapses- hydrogen bonding is more random
line spectrum
a spectrum containing radiation of only specific wavelength.
electrolyte
a substance (such as salt- NaCl) whose aqueous solutions contain ions
nonelectrolyte
a substance such as sucrose that does not form ions in solution
volatile
a substance that exhibits a vapor pressure
nonvolatile
a substance that has no vapor pressure
amphiprotic
a substance that is capable of acting as either an acid or a base. It acts as a base when combined with something more strongly acidic than itself, and as an acid when combined with something more strongly basic than itself.
acid
a substance whose molecules yield hydrogen ions (H+) when dissolved in water. can be considered to be composed of an anion connected to enough H+ ions to neutralize, or balance, the anion's charge.
enthalpy
accounts for heat flow in processes occurring at constant pressure when no forms of work are performed other than P-V work
The Bronsted Lowry concept of acids and bases
acid-base reactions involve the transfer of H+ ions from one substance to another
carboxylic acids
acids that contain a carboxyl group COOH
enzyme inhibitors
activity of an enzyme destroyed by the molecules that bond to active site and block substrates.
the number of carbon atoms in an alcohol
affects its solubility in water
significant figures
all digits of a measured quantity, including the uncertain one
inorganic compounds
all other compounds besides the organic. they are associated with the nonliving portion of our world. There are three categories: ionic compounds, molecular compounds, and acids.
metallic elements, metals
all the elements on the left side and in the middle of the periodic table, except for hydrogen.
the speed of light
all types of electromagnetic radiation move through a vacuum at a speed of 3.00 x 10^8 m/s
three types of radiation:
alpha, beta, gamma
complex ion
an assembly of a metal ion and the Lewis bases bonded to it
molecule
an assembly of two or more atoms tightly bound together
bonding atomic radius, covalent radii
an atomic radius based on the distances separating the nuclei of atoms when they are chemically bonded to each other. it is shorter than the nonbonding atomic radius. used to determine how much the spheres interpenetrate each other
unpaired electron
an electron not accompanied by a partner of opposite spin in its orbital.
anion
an ion with a negative charge
cation
an ion with a positive charge
physical properties
can be measured without changing the identity and composition of the substance. color, odor, density, melting point, boiling point, hardness
empirical formulas
chemical formulas that give only the relative number of atoms of each type in a molecule
molecular formulas
chemical formulas that indicate the actual numbers and types of atoms in a molecule Summarizes the composition of the substance but does not show how the atoms come together to form the molecule.
mixture
combination of two or more substances in which each substance retains its own chemical identity
active metals
metals that are most easily oxidized, that is, they react most readily to form compounds. They are at the top of the activity series, such as the alkali metals and the alkaline earth metals
3 simplest alkanes
methane- one carbon atom ethane- two carbon atoms propane- 3 carbon atoms
most reaction rate data obey the Arrhenius equation based on 3 factors:
1. fraction of molecules possessing an energy of Ea or greater 2. number of collisions occurring per second 3. fraction of collisions that have appropriate orientation.
Noble gases are stable because:
1. high ionization energies 2. low affinity for additional electrons. 3. general lack of chemical reactivity.
dipole
established whenever two electrical charges of equal magnitude but opposite sign are separated by a distance.
enthalpy diagram
-exothermic- enthalpy products < reactants (energy lost --> heat released to surroundings) 1. enthalpy is an extensive property ( deltaH is proportional to amount of reactant consumed) 2. the enthalpy change for a reaction is equal in magnitude, but opposite in sign, to deltaH for the reverse reaction. 3. the enthalpy change for a reaction depends on the state of the reactants and products. deltaH changes between (s), (l), (g) -important to specify states of reactants and products in thermochemical equations.
initial pH
-log of initial concentration of strong acid
4 types of IMFs
1 dipole dipole 2 London dispersion 3 Hydrogen bonding 4 Ion-dipole 1-3 are van der waals forces 4 important in solutions 1 and 4 are electrostatic in nature. (involving attractions between positive and negative species) less than 15% as strong as covalent or ionic
parts per billion (ppb)
1 ppb represents 1g of solute per billion (10^9) grams of solution, or 1 microgram of solute per liter of solution
Group 1, 2, 3 elements will contain cations with charges
1+, 2+, 3+
R in various units:
1. 0.08206 atom-L/mol-K 2. 8.314 J/mol-K 3. 1.987 cal/mol-K 4. 8.314 m^3-Pa/mol-K 5. 62.36 torr-L/mol-K units of P,V, n, and T must agree with gas constant
combined effect of cation and anion in solution
1. An anion that is the conjugate base of a strong acid will not affect the pH of the solution. 2. An anion that is the conjugate base of a weak acid will cause an increase in pH. 3. A cation that is the conjugate acid of a weak base will decrease pH. 4. The cations of Group 1 and heaver members of Group 2 will not affect pH. These are the cations of the strong Arrhenius bases 5. Other metal ions will cause a decrease in pH. 6. When a solution contains the CB of a weak acid and the CA of a weak base, the ion with the larger Ka or Kb will have a greater influence on pH.
to distinguish between first and second order rate laws:
1. Graph both ln[A]t and 1/[A]t against t. 2. If the ln[A]t plot is linear, then the reaction is first order 3. If the 1/[A]t plot is linear, the reaction is second order
rules for counting significant figures
1. Read number from left to right 2. start with the first digit that is not zero 3. all nonzero digits are significant 4. zeros between nonzero digits are always significant 5. zeros at the beginning of a number are never significant; they merely indicate the position of the decimal point. 6. zeros at the end of a number are significant if the number contains a decimal point.
We can use stoichiometry to deduce equilibrium concentrations:
1. Tabulate all the known initial and equilibrium concentrations of the species that are in the equilibrium constant expression. 2. For species which have known initial and equilibrium concentrations, calculate the change in concentration that occurs. 3. Use the stoichiometry of the reaction (the coefficients in the balanced chemical equation) to calculate the changes in concentration for all other species in the equilibrium. 4. From the initial concentrations and the changes in concentration, calculate the equilibrium concentrations. These are used to evaluate the equilibrium constant.
determining the number of moles of gas collected from a chemical reaction
1. a solid is heated 2. gas is released and bubbled trough water. 3. gas has been collected --> bottle is raised or lowered so water levels inside and outside are equal. 5. total pressure of gases inside the bottle is then equal to the atmospheric pressure.
the ideal gas equation...
1. accounts for the properties of most gases under a wide variety of circumstances 2. it is not correct for any real gas--real gases occupy close to 22.4 L per mole
two factors contribute to acidic behavior in carboxylic acids
1. additional oxygen atom attached to the carboxyl group carbon draws electron density from the OH bond, increasing polarity, stabilizing conjugate base. 2. conjugate base of a carboxylic acid (carboxylate anion) can exhibit resonance, which contributes further to the stability of the anion by spreading the negative charge over several atoms.
quantum theory is used to explain
1. arrangements of elements in the periodic table 2. trends in the periodic table 3. formation of bonds between atoms
to classify a soluble substance as a strong electrolyte, weak electrolyte, or nonelectrolyte:
1. ask yourself if the substance is ionic or molecular. 2. if it is ionic- it is a strong electrolyte because all ionic compounds are strong electrolytes. 3. if it is molecular- ask yourself if it is an acid or a base- does it have H first in the chemical formula? 4. if it is an acid, we rely on the memorized list of strong acids to determine whether it is a strong or weak electrolyte. 4. if it is a base, also refer to the memorized list of strong bases to determine whether it is a strong or weak electrolyte.
we can tell whether a compound is ionic or molecular from its composition:
1. cations are usually metal ions, whereas anions are nonmetal ions. 2. ionic compounds are generally combinations of metals and nonmetals. 3. molecular compounds are generally composed of nonmetals only.
naming of positive ions (cations)
1. cations formed from metal atoms have the same nme as the metal 2. ions formed from a single atom are called monatomic ions 3. if a metal can form different cations, the positive charge is indicated by a roman numeral in parentheses following the name of the metal
the integrated rate law can be used to
1. determine the concentration of a reactant remaining at any time after the reaction has started 2. the time required for a given fraction of a sample to react 3. the time required for a reactant concentration to fall to a certain level. 4. verify whether a reaction is first order + determine the rate constant
the principal reason ionic compounds are stable is the attraction between ions of unlike charge. This attraction:
1. draws the ions together. 2. releases energy 3. cause ions to form a solid lattice
atomic theory
1. each element is composed of extremely small particles called atoms 2. all atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of other elements 3. atoms of an element are not changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions. 4. compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms.
Bohr's two important ideas incorporated in the current model:
1. electrons exist only in certain discrete energy levels, which are described by quantum numbers. 2. energy is involved in moving an electron from one level to another.
Properties of gases
1. expand to fill container 2. volume of gas = volume of container 3. highly compressible 4. when pressure is applied, volume decreases 5. form homogenous mixtures with each other 6. individual molecules relatively far apart - each molecule behaves as if the others are not present - different gases behave similarly
solutions that are not ideal and don't obey Raoult's law occur when:
1. if the intermolecular forces between solvent and solute are weaker than those between solvent and solvent and between solute and solute, then the solvent vapor pressure tends to be greater than predicted by Raoult's Law 2. when the interactions between solute and solvent are exceptionally strong, as might be the case when hydrogen bonding exists, the solvent vapor pressure is lower than Raoult's law predicts.
how to specify the concentration of an electrolyte solution:
1. in terms of the compound used to make the solution or 2. in the terms of the ions that the solution contains.
Planck's quantum theory
1. matter is allowed to emit and absorb energy only in whole number multiples of hv 2. the allowed energies are quantized- their values are restricted to certain quantities- released only in specific amounts.
types of weak bases
1. neutral substances- have an atom with a nonbonding pair of electrons that can serve as a proton acceptor. 2. the anions of weak acids
Limitations of the Bohr Model
1. offers an explanation for the line spectrum of the hydrogen atom. 2. it cannot explain the spectra of other atoms. 3. there is a problem with describing an electron as just a small particle circling about the nucleus 4. the electron exhibits wavelike properties. 5. the bohr model was only an important step along the way toward the development of a more comprehensive model.
Two rules for oxyacids
1. oxyacids with the same number of OH groups and same number of O atoms: acid strength increases with increasing electronegativity of central atom Y. 2. oxyacids with the same central atom Y: acid strength increases as # of O atoms attached to Y increases (oxidation number of central atom increases)
Factors that affect the acid strength
1. polarity of H-X bond 2. strength of H-X bond 3. stability of the conjugate base, X-
to interconvert molarity and molality from the mass of the solute, solvent, and density of the solution
1. the mass of the solution is the sum of the masses of the solvent and solute 2. the volume of the solution can be calculated from its mass and density see page 547
naming of negative ions (anions)
1. the names of monatomic ions are formed by replacing the ending of the name of the element with -ide. 2. polyatomic ions containing oxygen have names ending in -ate or -ite.
factors that allow us to change the rate at which a reaction occurs
1. the physical state of the reactants gas or liquid- homogenous mixture-collisions solid- increase surface area 2. the concentrations of the reactants 3. the temp at which the reaction occurs> more KE> more collisions 4. the presence of a catalyst
to balance a metathesis reaction
1. use the chemical formulas of the reactants to determine that ions that are present. 2. write the chemical formulas of the products by combining the cation from one reaction with the anion of the other. (use the charges of the ions to determine the subscripts in the chemical formulas) 3. balance the equation.
how to write net ionic equations:
1. write a balanced molecular equation for the reaction. 2. rewrite the equation to show the ions that form in solution when each soluble strong electrolyte decomposes into its component ions. Only strong electrolytes dissolved in aqueous solution are written in ionic form. 3. Identify and cancel spectator ions.
How to predict the molecular geometry of a molecule or ion:
1.) Draw the Lewis structure 2.) Determine the electron domain geometry by arranging the electron domains about the central atom so that the repulsions among them are minimized. 3.) Use the arrangement of bonded atoms to determine the molecular geometry
types of exceptions to the octet rule
1.) molecules and polyatomic ions containing an odd number of electrons 2.) molecules and polyatomic ions in which an atom has fewer than an octet of valence electrons (most common in Boron and beryllium compounds) 3.) molecules and polyatomic ions in which an atom has more than an octet of valence electrons(largest class of exceptions- observed only for elements in period 3 and beyond in the periodic table- can use their empty d orbitals to accommodate additional electrons)
Procedure for drawing Lewis structures:
1.) sum the valence electrons from all the atoms. 2.) write the symbols for the atoms to show which atoms are attached to which, and connect them with a single bond (a dash representing two electrons) -chemical formulas are often written in order in which atoms are connected in molecule or ion. -the central atom is usually first, generally less electronegative than the atoms surrounding it. 3. Complete the octets around all the atoms bonded to the central atom. 4. Place any leftover electrons on the central atom, even if doing so results in more than an octet of electrons around the atom. 5. If there are not enough electrons to give the central atom an octet, try multiple bonds. -use one or more of the unshared pairs of electrons on the atoms bonded to the central atom to form double or triple bonds.
Reaction occurs in two steps:
1.) we supply enough energy to break those bonds in the reactants that are not present in the products. - the enthalpy of the system is increased by the sum of the bond enthalpies of the bonds that are broken. 2.) we form the bonds in the products that were not present in the reactants. -this step lowers the enthalpy of the system by the sum of the bond enthalpies of the bonds formed--energy is released. -enthalpy of the reaction, deltaHrxn, is estimated as the sum of the bond enthalpies of the bonds broken minus the sum of the bond enthalpies of the bonds formed.
beginning with the n=3 shell, each shell has __ d orbitals
5
Avogadro's number
6.022 x 10^23 atoms is 12 g of isotopically pure Carbon 12
The pH of a neutral solution @ 25 degrees C is?
7.00
pH
A figure representing the acidity or alkalinity or a solution on a logarithmic scale on which 7 is neutral, lower values are more acidic, and higher values are more alkaline
pure substance
matter that has distinct properties and a composition that doesn't vary from sample to sample.
To convert Fahrenheit into Celsius
C = 5/9(F- 32)
To convert Kelvin into Celsius
C = K - 273.15
when hydrocarbons are combusted in air, they react with O2 to form...
CO2 and H2O
carbonates and bicarbonates react with acids to form...
CO2 gas
Carbonic acid decomposes into
Carbon dioxide and water
Lewis symbols
Consists of a chemical symbol for the element plus a dot for each valence electron. The valence electrons in any representative element is the same as the group number of the element. For example, Oxygen and Sulfur have 6 dots.
the potential energy of 2 interacting charged particles is given by
Eel = KQ1Q2/d. Q1 and Q2 = charges of the particles d = distance between their centers. k = a constant = 8.99 x 10^9 J-m/c^2 This equation indicates the attractive interaction between 2 oppositely charged ions increases: 1. as the magnitude of their charges increase and 2. as the distance between their centers decreases (radii decrease)
Why is there a sharp increase in ionization energy when an inner shell electron is removed?
Ionizations increase steadily for the loss of the electrons in the outer subshells. Removal of the first inner shell electron requires a great deal of energy. This electron is more likely to be found close to the nucleus and experiences a greater effective nuclear charge than the outer shell electrons do.
the acid dissociation constant
Ka. Indicates the tendency of the acid to ionize in water: The larger the value of Ka, the stronger the acid.
SI unit for temperature
Kelvin
units of rate constant for a second order rate law
M^-1 s^-1
Robert Millikan's experiment
Oil Drop experiment
hybridization
the process of mixing atomic orbitals as atoms approach eachother to form bonds
If the weak base formed in hydrolysis is stronger than the weak acid formed
The overall solution will be basic
If the weak acid and base formed during hydrolysis are of equal strength
The overall solution will be neutral
If the weak acid formed in hydrolysis is stronger than the weak base formed
The overall solution will be slightly acidic
salt
any ionic compound whose cation comes from a base (for example, Na+ from NaOH) and whose anion comes from an acid (for example, Cl- from HCl)
isoelectronic series
a group of ions containing the same number of electrons. if listed in order of increasing atomic number, the nuclear charge increases as we move through the series. the number of electrons remains constant.
Ideal gas
a hypothetical gas whose pressure, volume, and temperature behavior is completely described by the ideal gas equation.
vapor pressure
a liquid in a closed container will establish an equilibrium with its vapor. when that equilibrium is reached, the pressure exerted by the vapor is called the vapor pressure
activity series
a list of metals arranged in order of decreasing ease of oxidation.
polar molecule
a molecule in which the centers of positive and negative charge do not coincide. these molecules align themselves with respect to one another, with the negative end of one molecule and the positive end of another attracting each other. these molecules are likewise attracted to ions. these interactions account for properties of liquids, solids, and solutions.
reaction quotient Q
a number obtained by substituting starting reactant and product concentrations or partial pressures into an equilibrium constant expression.
state function
a property of a system that is determined by specifying the system's condition, or state (temperature, pressure, location, etc.)
the dipole moment of a diatomic molecule is
a quantitative measure of the amount of charge separation in the molecule.
electron domain
a region in which the electrons will most likely be found.
metal oxides that react with acids form
a salt plus water
most nonmetal oxides dissolve in basic solutions to form
a salt plus water
standard state
a set of conditions at which most enthalpies are tabulated ( pure form at 1 atm and 298 K)
when strong electrolytes ionize, the reaction is written with...
a single arrow. ions have no tendency to recombine into molecules in water.
titration is?
a solution containing a known concentration of base is slowly added to an acid or acid to base
strength of its conjugate base
ability to accept protons
strength of an acid
ability to donate protons
buffers most effectively resist a change in pH in either direction when the concentrations of weak acid and conjugate base are
about the same
pH at the equivalence point is always _____ 7 in a weak acid strong base titration because
above 7 because the anion of the salt formed is a weak base.
energy must be ____________ for an electron to move to a higher energy state
absorbed
titration can be conducted with ____, ___, ____ reactions
acid-base, oxidation-reduction, precipitation
nonmetal oxides are (basic or acidic)
acidic
nonmetal oxides dissolve in water to form
acidic solutions
naming acids
acids containing anions whose names end in -ide are named by changing the -ide to -ic, adding the prefix hydro- to this anion name, and then following with the word acid.
acid and base characteristics
acids have a sour taste and cause certain dyes to change color bases have a bitter taste and feel slippery
oxyacids
acids in which OH groups and possibly additional oxygen atoms are bound to a central atom.
diprotic acids
acids that yield two H+ ions per molecule of acid. For example, H2SO4, sulfuric acid.
buffer capacity
amount of acid or base the buffer can neutralize before the pH begins to change to an appreciable degree.
atomic mass unit
amu one amu = 1.66 x 10 ^ -24 grams one proton has a mass of 1.0073 amu one neutron 1.0087 amu an electron has 5.485 x 10 ^ -4 amu (1836 electrons equal one proton) the nucleus thus contains most of the mass of an atom
conjugate acid-base pair
an acid and a base such as HX and X- that differ only in the presence or absence of a proton.
ionic equation
an equation written in this form has all soluble strong electrolytes shown as ions.
combustion analysis
an experimental technique by chemists to determine empirical formulas. It is commonly used for compounds containing carbon and hydrogen as their component elements. The carbon compound is converted to CO2 and hydrogen into H2O. The amounts of carbon dioxide and H2O produced are determined by measuring the mass increase in the CO2 and H2O absorbers. From the masses, we can calculate the number of moles of C and H in the original compound. If the third element is present in the compound, its mass can be determined by subtracting the masses of C and H from the compound's mass.
theory
an explanation of the general causes of certain phenomena, with considerable evidence or facts to support it.
precipitate
an insoluble solid formed by a reaction in solution
node
an intermediate point at which a probability function goes to zero. there is zero probability of finding the electron at a distance corresponding to the node.
supercooling
as we remove heat from a liquid, it can be supercooled below its boiling point without forming a solid. heat is removed from a liquid so rapidly that the molecules have no time to assume the ordered structure of a solid. supercooled liquid is unstable, particles of dust or gentle stirring is sufficient to cause the substance to solidify quickly.
Law of combining volumes
at a given pressure and temperature, the volumes of gases that react with one another are in the ratios of small whole numbers.
noble metals
at the bottom of the activity series; transition elements- very stable- form compounds less easily. they are used to make coins and jewelry
Moseley developed the concept of
atomic numbers. He determines that the frequencies of X rays emitted as different elements were bombarded with high energy electrons. Found that each element produces X rays of a unique frequency. The frequency generally increased as the atomic mass increased. Arranged the x ray frequencies in order by assigning a unique whole number, called an atomic number, to each element. Correctly identified the atomic number as the number of protons in the nucleus of the atom and the number of electrons in the atom..
isotopes
atoms with identical atomic numbers but different mass numbers
negative electron affinity + high ionization energy =
attract electrons + resist having them attracted away = high electronegativity
particles with unlike charges....
attract one another
using quantum mechanics, calculate the distribution of electron density I molecules.
attractions between nucleus and electrons cause electron density to concentrate between nuclei. overall electrostatic interactions are attractive. Nuclei attracted to concentration of negative charge between them, H atoms are held together in H2.
differences in the strengths of dipole dipole attractions cause differences in magnitudes of _________ forces
attractive
2 of the five domains in the trigonal bipyramidal electron domain geometry point toward ___ positions
axial
the presence of ions causes aqueous solutions to....
become good electrical conductors.
compound
composed of two or more substances in which each substance retains its own chemical identity
Molecular compounds
compounds that are composed of molecules and contain more than one type of atom
organic compounds
compounds that contain carbon and hydrogen, often in combination with oxygen, nitrogen, or other elements.
hydrocarbons
compounds that contain only carbon and hydrogen binary molecular compounds but with a different name than the inorganic binary compounds
pH before the equivalence point=
concentration of acid not yet neutralized
scientific law
concise verbal statement or mathematical equation that summarizes a broad variety of observations and experiments > describe behavior of matter
the pH of an aqueous salt solution can be predicted by
considering the ions of which the salt is composed.
polyatomic ions
consist of atoms joined as in a molecule, but they have a net positive or negative charge
naming of ionic compounds
consist of cation name followed by the anion name
pH meter
consists of a pair of electrodes connected to a meter capable of measuring small voltages, on the order of millivolts. A voltage, which varies with the pH, is generated when the electrodes are placed in a solution. This voltage is read by the meter, which is calibrated to give pH.
Effect of a volume increase at constant temperature
constant temp = average kinetic energy unchanged rms speed, u, unchanged. volume increased ---> molecules move a longer distance between collisions fewer collisions = pressure decreases. accounts for Boyle's Law.
organic compounds
contain carbon, usually in combination with hydrogen, oxygen, nitrogen or sulfur. associated with plants and animals
net electric field
created by the nucleus and the electron density of other electrons. We can estimate the net attraction of each electron to the nucleus and the electron density of the other electrons.
meniscus
curved upper surface in glass because the adhesive forces between the water and the glass are greater than the cohesive forces between the water molecules
when n is 3 or greater, we encounter the __ orbitals
d
within each row, period, atomic radius tends to _________ from left to right.
decrease. this is caused by the increase in the effective nuclear charge as we move across a row. it steadily draws valence electrons closer to the nucleus, causing the atomic radius to decrease.
down a group, bond strength ______ and acidity _______
decreases, increases
within each group of the periodic table, the ionization energy _______ with increasing atomic number.
decreases.
bonding pair
defines a region in which the electrons will most likely be found
enthalpies of vaporization
delta H liquid to gas
We can calculate the enthalpy change of the system for each of the heating curve segments
deltaH = mCdeltaT greater specific heat > more heat to raise temp T is constant because added energy is used to overcome attractive forces between molecules rather than increase their average kinetic energy
is light a wave or does it consist of small particles?
depending on the situation, the light will behave more like a wave or more like particles.
distillation
depends on the different abilities of substances to form gases. example- boiling salt water to separate water and salt through evaporation and then condensation in the walls of a condenser.
space filling model
depicts what the molecule would look like if the atoms were scaled up in size. show the relative sizes of atoms, but the angles between atoms, which help define their molecular geometry, are more difficult to see.
u = square root (3 RT / M)
derived from kinetic molecular theory. expresses quantitatively: 1. the mass m of particles in the lighter gas is smaller than the heavier gas. 2. particles of the lighter gas must have a higher rms speed, u, then the particles of the heavier one. 3. because molar mass appears in the denominator, the less massive the gas molecules, the higher the rms speed, u.
volume
derived from the length of an object cubed
chemical properties
describe the way a substance may change, or react, to form other substances
sp2
directed toward trigonal planar geometry
sp3
directed toward vertexes of a tetrahedron
sp3d
directed toward vertices of a trigonal bipyramid
sp3d2
directed toward vertices of an octahedron
molecules of 2 subsstances with comparable molecular weights and shapes have approximately equal ________ forces
dispersion
larger molecules > greater polarizability > greater number of electrons > electrons further from the nucleus >
dispersion forces tend to increase in strength with increasing molecular weight
ionization
dissociating into ions. For example, when HCl(g) dissolves in water to form hydrochloric acid, it dissociates in H+ (aq) and Cl-(aq) ions.
electron affinities _____ as we move down a group
do not change greatly because lower electron nucleus attraction is counterbalanced by lower electron electron repulsions.
intensive properties
do not depend on the amount of a sample being examined. such as temperature, melting point, density
acid base indicators
dyes that indicate the equivalence point of a titration by changing color.
It is always _______ to remove the first proton from a polyprotic acid than to remove the second
easier
the internuclear axis
electron density of covalent bonds is concentrated symmetrically about the line connecting the nucleus. the line that joins 2 nuclei passes through the middle of the overlap region
lewis acid
electron pair acceptor
electron spin
electrons have an intrinsic property that causes each electron to behave as if it were a tiny sphere spinning on its own axis.
nonpolar covalent bond
electrons shared equally between 2 atoms
radiant energy is _______ when the electron jumps to a lower energy state
emitted
getting the distances between ions in an ionic solid lattice to increases until they're very far part is a highly _________ process.
endothermic
gas laws
equations that represent relationships among T,P,V,n
3 of the five domains in the trigonal bipyamidal electron domain geometry point toward _____ positions
equatorial
because the domains from nonbonding pairs exert larger repulsions than those from bonding pairs, and we must determine which location minimizes the repulsions between the electron domains, nonbonding electron domains always occupy the ______ positions in a trigonal bipyramid
equatorial
If Q = Ksp
equilibrium exists (saturated solution)
heterogeneous catalyst
exists in a different phase from the reactant molecules, usually as a solid in contact with either gaseous reactants or with reactants in a liquid solution. -often composed of metal or metal oxides
the coming together of Na and Cl to form NaCl is an _________ process.
exothermic
when a nonmetal gains an electron, the process is generally ____________
exothermic, as seen from the negative electron affinities of the elements.
molarity
expresses the concentration of a solution as the number of moles of solute in a liter of solution. M = mol/ L
law of mass action
expresses, for any reaction, the relationship between the concentrations of the reactants and products present at equilibrium.
equation for the fraction of molecules that has an energy equal to or greater than Ea
f = e^-Ea/RT R = gas constant = 8.314 J/ mol-K T = absolute temperature f is usually a small #
the Zeff for valence electrons changes ____ in a row than when going down a column.
far less
lower Ea > _____ reaction
faster
covalent network solids
form of unit particles: atoms connected in a network of covalent bonds forces between particles: covalent bonds properties: very hard, very high melting point, often poor thermal and electrical conduction examples: diamond, Cl quartz, SiO2 more: graphite is a good conductor of electricity becaue of electron in its delocalized pi bond. C atoms are arranged in hexagonal rings in interconnected layers--held by weak dispersion--graphite is easily rubbed off.
molecular solids
form of unit particles: atoms or molecules held together by forces between particles: London dispersion, forces, dipole dipole forces, hydrogen bonding properties: fairly soft, low to moderately high melting point, poor thermal and electrical conduction examples: argon, Ar, methane, CH4, sucrose, C12H22O11, Dry ice, CO2 more: most substances that are gases or liquids at room temperature form molecular solids at low temperature properties depend on IMFs and packing abilities
greater enthalpy =
greater bond strength. A molecule with strong chemical bonds generally has less tendency to undergo chemical change than one with weaker bonds.
Planck's constant
h = 6.626 x 10^-34 J-s
summarizes the behavior of about 3 million compounds
hydrocarbons and other oxygen containing derivatives of hydrocarbons form carbon dioxide and water
alkali metals react in water to produce
hydrogen gas and a solution of an alkali metal hydroxide
soluble metal oxides dissolved in water form
hydroxide ions from the reaction of O2- ions with H2O.
bases produce what when they dissolve in water?
hydroxide ions: OH-
Most common soluble strong bases
hydroxides of the alkali metals and the heavier alkaline earth metals (NaOH, KOH, Ca(OH)2)
catalysts
increase reaction rates without being used up. they affect the kinds of collisions
when we have a gaseous substance distributed between the gas and solution phases, increasing the pressure will
increase the rate at which gas molecules strike the surface to enter the solution phase.
within each column, (group), atomic radius tends to ________ from top to bottom.
increase. this results from the increase in the principal quantum number n. The outer electrons have a greater probability of being farther from the nucleus, causing the atom to increase in size.
When a volume of gas is compressed (decreases) the pressure of the gas ________
increases
as we proceed down a group in the periodic table, metallic character generally
increases
as we proceed from right to left in a period of the periodic table, metallic character generally
increases
increasing pressure or decreasing temperature ______ intermolecular attraction
increases
the distance between bonded atoms decreases as the number of shared electron pairs
increases
the solubility of an alcohol in a nonpolar solvent like hexane (C6H14) _________ as the nonpolar hydrocarbon chain increases in length
increases
the solubility of most solid solutes in water increases as the temperature of the solution
increases
the strength of an H-X bond tends to decrease as the element X ________ in size
increases
when the nuclear charge increases, the force of attraction between an electron and the nucleus
increases
across a period the effective nuclear charge
increases and the atomic radius decreases, causing the ionization energy to increase.
for ions carrying the same charge, size ______ as we go down a column in the periodic table
increases as the principal quantum number of the outermost occupied orbital of an ion increases, the radius of the ion increases.
The effective nuclear charge __________ as we go down a group because larger electron cores are less able to screen the outer electrons from the nuclear charge.
increases slightly
between the initial pH and the equivalence point the graph
increases slowly
the effective nuclear charge ________ as we move across any row (the period of the periodic table) for valence electrons.
increases. the number of core electrons stays the same, but the actual nuclear charge increases because the valence electrons added to counterbalance the increasing nuclear charge shield one another ineffectively
Adding heat to an exothermic reaction
increasing T causes a shift to the left, so a decrease in K
Adding heat to an endothermic reaction
increasing T causes a shift to the right, so an increase in K
nonpolar liquids tend to be _________ in polar liquids
insoluble
amphoteric
insoluble oxides and hydroxides that can be made to dissolve in either acidic or basic solutions
Determining IMFS
interacting molecules or ion are ions involved? Yes ? Are polar molecules and ions both present? Yes? Ion dipole forces. Are ions involved? Yes? Are polar molecules and ions both present? No? Ionic Bonding. Are ions involved? No? Are polar molecules involved? No? Dispersion forces. Are ions involved? No? Are polar molecules involved? No? Are H atoms bonded to N, O, or F atoms? Yes? Hydrogen bonding. No? Dipole Dipole forces
formula for molality
moles solute/ kilograms of solvent unit of product= molal depends on mass of the solvent
dipole dipole forces
positive end of one neutral polar molecule is near a negative end of another effective only when polar molecules are very close together weaker than ion dipole forces sometimes the orientation is attractive or repulsice molecules spend more time near eachother overall net attraction for these forces to operate, molecules must get close together in the correct orientation. smaller molecular volumes --> higher dipole dipole attractive forces
to calculate the heat of combustion from the measured temperature increase in the bomb calorimeter, we must know the total heat capacity of the calorimeter, Ccal
q rxn = -Ccal x delta T
exchange reactions, or metathesis reactions
reactions in which positive ions and negative ions appear to exchange partners to conform to the following general equation: AX + BY > BX + AY precipitation reactions and acid base reactions conform to this pattern.
elementary reaction
reactions take place as a result of collisions between reacting molecules. collisions provide energy to allow molecules to rearrange. single event/ step
integrated rate law
rearrangement of the differential rate law ln[A]t = -kt + ln [A]o
pi bond
second kind of bond used to describe multiple bonding--results from the overlap between 2 p orbitals oriented perpendicularly to the internuclear axis. -covalent bond in which overlap region is above and below the internuclear axis. -unlike sigma, no probability of finding electrons on internuclear axis. -total overlap in a pi bond in less than a sigma bond. they are generally weaker than sigma bonds.
Dmitri Mendeleev and Lothar Meyer found that...
similar chemical and physical properties recur periodically when the elements are arranged in order of increasing atomic weight.
the alkali metals properties
soft metallic solids with characteristic metallic properties abundant in the earth's biological systems and plants. have low densities and melting points as we move down the group, the atomic radius increases and the first ionization energy decreases. have the lowest ionization energies for their period of the periodic table very reactive, readily sing electrons to form ions with a 1+ charge. they exist in nature only as compounds. they combine directly with most nonmetals. combine with H to form hydrides and S to form sulfides
vapors
substances that are liquids or solids under ordinary conditions can also exist in the gaseous state, where they are referred to as ______.
lock and key
substrate fits into active site products separate from enzyme
electronic structure
the arrangements of electrons in atoms 1. the number of electrons in an atom 2. their distribution around the nucleus 3. their energies
as the number of bonds between two atoms increases,
the bond grows stronger and shorter. there is a bond enthalpy increase and a bond length decrease.
knowing atomic radii allows us to estimate
the bond lengths between different elements in molecules
Valence bond theory
the buildup of electron density between 2 nuclei is visualized as occurring when a valence atomic orbital of one atom merges with that of another atom. orbitals share region of space = overlap.
energy
the capacity to do work or transfer heat
reactants
the chemical formulas to the left of the arrow, or the starting substances.
products
the chemical formulas to the right of the arrow, or the substances produced in the reaction
nonbonding atomic radius, van der waals radius
the closest distances separating the nuclei during atomic collisions determine the apparent radii. The electron clouds of colliding atoms cannot penetrate each other to any significant extent.
electron shell
the collection of orbitals with the same value of n
the observed bond length
the distance at which the attractive forces between unlike charges (electrons and nuclei) are balanced by the repulsive forces between like charges (electron-electron and nucleus-nucleus)
bond length
the distance between the nuclei of the atoms involved in a bond.
wavelength
the distance between two adjacent peaks or two adjacent troughs
lobes
the dumbbell shaped p orbital has two ____. the electron density is concentrated in two regions on either side of the nucleus, separated by a node at the nucleus.
amphoterism
the effects of both pH and complexing agents on the solubility of ionic compounds
condensed electron configuration
the electron configuration of the nearest noble gas element of lower atomic number is represented by its chemical symbol in brackets.
spherically symmetric
the electron density in the s orbital is this. At a given distance from the nucleus- the same regardless of the direction in which we proceed from the nucleus.
de Broglie suggested that...
the electron has associated with it a particular wavelength in its movement about the nucleus
if nf is smaller than ni ...
the electron moves closer to the nucleus and deltaE is a negative number. the negative sign is not included because the wavelength and frequency are always reported as positive quantities.
the outer shell electrons
the electrons given after the noble gas core.
valence electrons
the electrons involved in bonding. for lighter elements with an atomic number of 30 or less, all of the outer shell electrons are valence electrons.
noble gas core
the electrons represented by the symbol for a noble gas, or the core electrons.
potential energy
the energy of position PE = mgh
work
the energy used to cause an object with mass to move.
heat
the energy used to cause the temperature of an object to increase
We can use average bond enthalpies to estimate
the enthalpies of reactions in which bonds are broken and new bonds are formed > whether a reaction will be endothermic or exothermic
standard enthalpy change
the enthalpy change when all reactants and products are in their standard states (delta H)
bond enthalpy
the enthalpy change, delta H, for the breaking of a particular bond in one mole of a gaseous substance. it is always a positive quantity. Energy is required to break chemical bonds, and energy is released when a bond forms between two gaseous atoms or molecular fragments.
effusion
the escape of gas molecules through a tiny hole into an evacuated space
Celsius scale
the everyday scale of temperature in most countries
common ion effect
the extent of ionization of a weak electrolyte is decreased by adding to the solution a strong electrolyte that has an ion in common with the weak electrolyte.
how to calculate the average atomic mass
the fractional abundance of each isotope and the mass of that isotope(multiply for each isotope, add together)
as pressure increases, gas volumes tend to be greater than those predicted by the ideal gas equation. why?
the free space in which the molecules can move becomes a smaller fraction of the container volume
first order graph
the graph of ln[A]t vs time gives a straight line
lnK = -Ea/RT + lnA
the graph of lnk vs 1/T has slope of -Ea/RT + y intercept lnA
first law of thermodynamics
the heat absorbed by the liquid in vaporizing must be released when the reverse process, condensation of the vapor to form the liquid, occurs.
critical temperature
the highest temperature at which a distinct liquid phase can form
periods
the horizontal rows of the periodic table.
pressure
the idea of a force, a push that tends to move something in a given direction. P = F/ A the force, F, that acts on a given area.
As temperature increases, the behavior of the gas more nearly approaches that of
the ideal gas
sigma bonds
the line that joins two nuclei passes through middle of overlap region. examples: overlap of 2s orbitals, overlap of an s and p orbital, overlap of 2 p orbitals, overlap of p orbital and sp hybrid orbital
metallic character
the more an element exhibits the physical and chemical properties of metals, the greater it has this.
the greater the amount of solute dissolved in a certain amount of solvent...
the more concentrated the resulting solution.
hypertonic
the more concentration solution separated from a more dilute solution through a semipermeable membrane is said to be this with respect to the dilute solution.
valence orbitals
the occupied orbitals that hold the electrons involved in bonding. elements in the same column of the table hold the same number of electrons in their valence orbitals.
crystallization
the opposite of the solution process, in which collisions of solute particles into the surface of the solid solute in a solvent increase with their increased concentration in the solution. this can result in the solute particle's becoming reattached to the solid.
solutes
the other substances in the solution, which are said to be dissolved in the solvent.
pH range
the pH range over which the buffer acts effectively
activated complex
the particular arrangement of atoms at the top of the barrier of activation energy. aka the transition state
percentage composition
the percentage by mass contributed by each element in the substance.
matter
the physical material of the universe--anything that has mass and occupies space.
resonance structures
the placement of atoms in 2 alternative but equivalent lewis structures is the same, but the placement of electrons is different.
equivalence point
the point at which stoichiometrically equivalent quantities are brought together in a titration
as the length of a carbon chain increases
the polar OH group becomes a smaller part of the molecule
system
the portion we single out for study
the vapor pressure of a liquid is
the pressure exerted by its vapor when the liquid and vapor states are in dynamic equillibrium
critical pressure
the pressure required to bring about liquefaction at this critical temperature
radial probability density
the probability that we will find the electron at a specific distance from the nucleus
If two equal and opposite charges Q+ and Q are separated by a distance r, the magnitude of the dipole moment is
the product of Q and r. mu = Qr
ionic solid
the product of a combination reaction that occurs between a metal and a nonmetal.
When 2 equations are added to give a third, the equilibrium constant associated with the third equation equals
the product of the equilibrium constants for the 2 equations added together.
single bond
the sharing of a pair of electrons
localized bonding electrons
the sigma and pi electrons are associated totally with the two atoms that form the bond
formation constant Kf
the size of this can help judge the stability of a complex ion in aqueous solution.
a balanced equation should contain...
the smallest possible whole number coefficients.
when a molecular compound dissolves in water...
the solution usually consists of intact molecules dispersed throughout the solution.
If Kb is greater than Ka,
the solution will be basic.
the majority of an atoms volume
the space in which electrons reside.
internal energy of a system is
the sum of all the kinetic and potential energies of all its components
Hess's Law
the sum of enthalpy changes of individual steps must be the same as enthalpy change of the one step process
isotonic
two solutions of identical osmotic pressure are separated by a semi permeable membrane. No osmosis will occur.
intermediates are usually
unstable molecules that have a low, unknown concentration
Rydberg Equation
used to calculate the wavelengths of all the spectral lines of hydrogen
formal charge
used to decide which lewis structure is the most reasonable when we can draw several different Lewis structures that all obey the octet rule. it is the charge the atom would have if all the atoms in the molecule had the same electronegativity. That is, if each bonding electron pair in the molecule were shared equally between its two atoms.
bomb calorimeter
used to measure heat accompanying combustion reactions @ constant volume
manometer
used to measure pressure of enclosed gases
chemical formula
used to represent the molecular form of an element
