Chemistry Final
solution
A homogeneous mixture of two or more substances
Solvent
A liquid substance capable of dissolving other substances
surface tension
A measure of how difficult it is to stretch or break the surface of a liquid. Water has a high surface tension because of the hydrogen bonding of surface molecules.
Rank the following substances in terms of increasing melting point: hydrofluoric acid (hydrogen fluoride), ethane, calcium chloride, dinitrogen monoxide.
C₂H₆, N₂O, HF, CaCl₂
base (b/l)
H+ acceptor
What is the [H+] of a solution with a pH of 12.85? What is the [OH-]?
H+= 1.41*10⁻¹³M H+ pOH= 1.15
hydronium ion
H3O+ equal to H+ and water
Phosphoric acid (H3PO4) has three 'acidic' hydrogens while hydrochloric acid only has one. Phosphoric acid is a weak acid and hydrochloric acid is a strong acid. Explain.
H3PO4 is a weak acid because it does not ionize completely while hydrochloric does ionize completely. A higher degree of ionization makes a weaker acid while a lower degree makes a stronger acid.
Base the answers to questions below on the information based on the heating curve below. Given the heating curve where substance X starts as a solid below its melting point and is heated uniformly: Identify a line segment in which the average kinetic energy is increasing.
AB CD and EF
product
Substance after the arrow
reactant
Substance before the arrow
reactants
Substance before the arrow
The concentration of reactant A doubled but the rate of reaction did not change. What is the order of reaction with respect to A? In the same reaction, the concentration of reactant B tripled and the rate of the reaction also tripled. What is the order of the reaction with respect to B?
The reaction is 0th order with respect to A. The reaction is 1st order with respect to B.
acid (b/l)
a compound that produces hydrogen ions in solution H+ donor
mole ratio
a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles
heat of vaporization
amount of heat required to convert a liquid into a gas at constant temperature and pressure
word equation
an equation in which reactants and products in a chemical reaction are represented by words
covalent bonding
bond in which electrons are shared between two non-metals
intermolecular force
forces of attraction between molecules
London dispersion forces
induced dipole-induced dipole force; always present
diatomic
made up of 2 atoms of the same element n₂
Elastic collision
total kinetic energy of the colliding bodies or particles is the same after the collision as it was before
Dalton's Law
total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture P=p1+p2+p3
Charles' Law
volume and temperature are directly related V1/T1=V2/T2
Water has a significantly higher surface tension than hexane (C6H14). Explain.
water's dominant IMF is Hydrogen bonding while Hexane's highest IMF is LDF. Surface tension and IMF are directly related and so water has a higher surface tension.
ionic bonding
one atom loses electrons and one atom gains electrons producing a complete positive and complete negative atom resulting in an attraction between the two
Kinetic Molecular Theory
the theory that all matter is composed of particles (atoms and molecules) moving constantly in random directions
reaction profile
theoretical representation of a single energetic pathway, along the reaction coordinate, as the reactants are transformed into products
molecular geometry
three-dimensional arrangement of the atoms that constitute a molecule
Molarity
A concentration unit of a solution expressed as moles of solute dissolved per liter of solution
subscript
Number of each element in a compound (mole ratio)
binary
atoms from 2 different elements diphosphorus pentoxide
dipole-dipole forces
attractions between partial positive of one and partial negative of another
weak acid
doesn't dissociate completely
weak base
doesn't dissociate completely
Valence electrons
electrons in the highest occupied energy level
single replacement reaction
element and compound create a different element and different compound
Is this reaction exothermic or endothermic?
endothermic
Base the answers to questions below on the information based on the heating curve below. Given the heating curve where substance X starts as a solid below its melting point and is heated uniformly: Identify the process that takes place during line segment DE of the heating curve.
evaporation
How are temperature and reaction rate related? Explain.
temperature and reaction rate are directly related because temperature increases the kinetic energy of the reactants (velocity) By increasing the temperature there are more reactant collisions and a greater fraction of effective collisions.
Would a catalyst lower the activation more, less, or no change on a reaction at 25°C or the same reaction at 100°C?
temperature doesn't change the effectiveness of a catalyst
electronegativity
tendency of an atom to attract electrons in a covalent bond
Combined Gas Law
(P1V1)/T1=(P2V2)/T2
Kinetic Molecular Theory/Gasses
-the particles of a gas in rapid random constant motion -the particles of a gas are considered to be small, hard spheres with insignificant volume -collisions of gas particles are perfectly elastic -no forces of attraction or repulsion between gas particles -average kinetic energy=the absolute temperature
28.45 mL of sulfuric acid (hydrogen sulfate) require 42.83 mL of 0.115 M potassium hydroxide to titrate to a phenolphthalein endpoint. What is the molarity of the sulfuric acid?
.0866 M H₂SO₄
What is the heat of reaction?
10KJ/mol
What are factors that impact the rate of a chemical reaction?
1. reactant concentration 2. temperature 3. surface area of reactants 4. catalyst
What is the activation energy for this reaction?
105KJ/mol
The reaction of iodide ion with hypochlorite ion, OCl- (which is found in liquid bleach), follows the equation: OCl- + I- ----> OI- + Cl- It is a rapid reaction that gives the following rate data. Initial Concentrations Rate of Formation [OCl-] [I-] (mol L-1 s-1) (mol/L) of Cl- 1.7 X 10-3 1.7 X 10-3 1.75 X 104 3.4 X 10-3 1.7 X 10-3 3.50 X 104 1.7 X 10-3 3.4 X 10-3 3.50 X 104 What is the order of reaction for the OCl- ion and the I- ion?
1st order with respect to OCl Oth order with respect to I
double replacement reaction
2 compounds create 2 different compounds
The graph below represents the heating curve of a substance that starts as a solid below its freezing point. What is the melting point of this substance?
55°C
skeleton equation
A chemical reaction that is not balanced
coefficient
A number in a chemical equation that indicates how many particles of a reactant or product are required or formed in the reaction.
coefficients
A number in a chemical equation that indicates how many particles of a reactant or product are required or formed in the reaction.
synthesis reaction
A reaction in which two or more substances react to form a single substance.
Inversely proportional
A relationship in which one variable decreases when another variable increases.
solute
A substance that is dissolved in a solution.
catalyst
A substance that speeds a chemical reaction by lowering the activation energy of the reaction.
How is a binary substance different from a diatomic substance?
Binary substances contain different elements but diatomic substances are two of the same elements
Base the answers to questions below on the information based on the heating curve below. Given the heating curve where substance X starts as a solid below its melting point and is heated uniformly: Describe, in terms of particle behavior or energy, what is happening to substance X during line segment BC.
During this time substance X is melting which means that although energy is being added, the temerature doesn't change because the bonds are breaking.
Pressure
Force per unit area.
Determine the dominant IMF present in the following compounds: ammonia
Hydrogen bonding
What is the relationship between IMF and melting point?
IMF and melting point are directly related
What MUST happen for any reaction to occur?
In order for a reaction to occur reactants must collide
Determine the dominant IMF present in the following compounds: carbon tetraiodide
LDF
Determine the dominant IMF present in the following compounds: oxygen
LDF
Identify ALL the IMF's present in: water
LDF dipole-dipole hydrogen bonding
Identify ALL the IMF's present in: Phosphorous trichloride
LDF Dipole-dipole
law of conservation of mass
Mass cannot be created or destroyed, mass of reactants and products must be equal
pOH
Measures the basicity of a solution. It is the negative log of the concentration of the hydroxide ions.
Identify the conjugate acid base pairs for the reaction of ammonia with water.
NH₃+H₂O→NH₄+OH B A CA CB
combustion reaction
O₂ is one of the reactants
Ideal Gas Law
PV=nRT
collision theory
States that atoms, ions, and molecules must collide in order to react.
Why does sugar dissolve more quickly in hot water than in cold water? Note, dissolution a substance being dissolved is NOT a chemical reaction.
Sugar dissolves quicker in hot water than cold water because the hot water increases the rate of reaction making the sugar dissolve faster.
heat of fusion
The amount of heat required to melt a substance
sublimation/deposition point
The temperature at which a gas changes to a liquid/liquid changes to a gas
boiling/condensation poit
The temperature at which a liquid becomes a gas/gas becomes a liquid
melting/freezing poing
The temperature at which a solid becomes a liquid/liquid becomes a solid
strong base
a base that completely dissociates into metal ions and hydroxide ions in aqueous solution
hydroxide ion
a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a covalent bond, and carries a negative electric charge
heating/cooling curve
a line graph that represents the change of phase of matter, typically from a gas to a solid or a liquid to a solid. The independent variable (X-axis) is time and the dependent variable (Y-axis) is temperature.
pH
a number used to denote the hydrogen-ion concentration or acidity of a solution -log[hydrogen ion concentration]
endotherm
a process that absorbs heat (bond breaking)
exotherm
a process that gives off heat (bond forming)
neutralization reactoin
a reaction between an acid and base that results in the product of water and a salt
decomposition reaction
a reaction in which a compound breaks down into two or more elements
precipitate
a solid (insoluble compound) that is formed when 2 solutions are mixed
titration
a solution of known concentration is used to determine the concentration of an unknown solution
products
a substance produced in a chemical reaction
volatility
ability to form a vapor
acid (Arrhenius)
acid (arrhenius) contains H+
strong acid
acid that dissociates completely in water
hydrogen bonding
an intermolecular attraction between molecules that exert a strong pull on their electrons. This attraction keeps the two strands of a DNA molecule together.
limiting reactant
any reactant that is used up first in a chemical reaction it determines the amount of product that can be formed in the reaction
excess reactant
any reactant that remains after the limiting reactant is used up in a chemical reactant
indicator
any substance that gives a visible sign, usually by a color change, of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution
Which substance has the highest vapor pressure, carbon dioxide or sulfur dioxide. Explain.
carbon dioxide has the highest vapor pressure because it has a lower IMF of LDF. Sulfur dioxide has dipole-dipole and IMF and vapor pressure are inversely related
base (Arrhenius)
contains OH-
polar covalent bonds
covalent bonds that have a separation of charge
chemical equation
depiction of a chemical reaction using chemical formulas and symbols
chemical formula
depiction of a chemical reaction using chemical formulas and symbols
Lewis Structures
diagrams that depict the arrangement of atoms around a central atom
Determine the dominant IMF present in the following compounds: CH2O
dipole-dipole
Determine the dominant IMF present in the following compounds: carbon monoxide
dipole-dipole
Determine the dominant IMF present in the following compounds: sulfur dioxide
dipole-dipole
Draw a reaction profile that shows how a catalyst increases the rate of a chemical reaction.
know how to do it
polar molecules
molecules that have ae separation of charge
Gay-Lussac's Law
pressure and temperature are directly related P1/T1=P2/T2
Boyles Law
pressure and volume are inversely related P1V1=P2V2
vapor pressure
pressure caused by the vaporization of a liquid or a solid
Stoichiometry of gasses
quantitative relationship (ratio) between reactants and products in a chemical reaction with reactions that produce gases
rules of solubility
soluble= not percipitate
hydrocarbon
substance that contains hydrogen and carbon along with other elements
theoretical yield
the amount of product that could form during a reaction calculated from a balanced chemical equation max amount of product that could be formed from a given amount of reactant
actual yield
the amount of product that forms when a reaction is carried out in the lab
kinetics
the branch of chemistry or biochemistry concerned with measuring and studying the rates of reactions.
hydrogen ion
the cation H+ of acids consisting of a hydrogen atom whose electron has been transferred to the anion of the acid
Base the answers to questions below on the heating curve, which represents a substance starting as a solid below its melting point and being heated at a constant rate over a period of time. How does this heating curve illustrate that the heat of vaporization is greater than the heat of fusion?
the change of the heat of vaporization is higher than that of the heat of fusion. segment BC is shorter that DE because BC is melting while DE is evaporating.
Directly proportional
the connection between two variables that shows the same effect (they both increase or both decrease)
order of reaction
the index, or exponent, to which its concentration term in the rate equation is raised
Base the answers to questions below on the heating curve, which represents a substance starting as a solid below its melting point and being heated at a constant rate over a period of time. What is happening to the average kinetic energy of the particles during segment BC?
the kinetic energy is constant
activation energy
the minimum energy colliding particles must have in order to react
equivalence point
the moles of acid are equivalent to the moles of base
endpoint
the point in a titration at which a reaction is complete, often marked by a color change.
stoichiometry
the portion of chemistry dealing with numerical relationships in chemical reactions
percent yield
the ratio of the actual yield to the theoretical yield for a chemical reaction expressed as a percentage actual yield/theoretical yield *100