Chemistry H. "Final Exam"
A 1.3 M solution of CaCl₂ in water has a density of 1.11 g/mL. What is the molality?
1.35 m CaCl₂
A solution prepared by dissolving a 4 g KCl in 36 g H₂O is said to be
10% KCl by mass
A solution is 2.25% by mass NaHCO₃ are in 450 g of solution
10.1 g
A solution cotains 11% by mass of sodium chloride. This mean that
100 g of the solution contains 11 g of sodium chloride
The angles between sp² orbitals are
120º
What volume of 0.716 M KBr solution is needed to provide 10.5 g of KBr?
123 mL
At 570 mmHg and 25ºC, a gas sample has a volume of 2270 mL. What is the final pressure (in mmHg) at a volume of 1250 mL and a temperature of 175ºC?
1560 mmHg
The angles between sp³d orbitals are
180º, 120º, 90º
What is the angle between adjacent sp³ hybrid orbitals?
190.5º
What is the molarity of sodium chloride in solution that is 13% by mass sodium chloride and has a density of 1.1 g/ml?
2.45
25. mL of alcohol is dissolved in water and the solution is diluted to a total final volume of 125 mL. What is the final concentration of ethanol?
20% (v/v)
The percentage s-character in sp³ hybridization
25%
The following reaction takes place when an electric current is passed through water. It is an example of a __________ reaction.
2H₂O (l) --(electricity)--> 2H₂ (g) + O₂ (g)
A triple covalent bond contains _______ of electrons
3 pairs
Convert to the equivalent pressure in atmospheres, 421 kPa.
4.15 atm
What is the mass percent oxygen in sodium carbonate, Na₂CO₃?
45.3%
An aqueous solution containing 1.0 g ephedrine in 20.0 mL solution is said to be
5% ephedrine (mass/vol)
What is molality of ethanol in a ethanol in a solution made by dissolving 14.6 g of ethanol, C₂H₅OH, in 53.6 g of water?
5.91 m
The sp³d² atomic hyrbid orbital set accommodates ________ electron domains.
6
The formula weight of magnesium fluoride (MgF₂), rounded to one decimal place, is ______ amu.
62.3
How many grams of KBr are required to make 650 mL of a 0.115 M KBr solution?
8.9 g
A single sp³ hybrid orbital has
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According to VBT, the formation of a stable bond requires
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If a liter of CO₂ is compared to a liter of H, both at 25ºC and one atmosphere pressure, then
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In a typical multiple bond, the σ bond results from overlap of __________ orbitals and the π bond(s) result from overlap of ___________ orbitals.
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Lead, water, sulfure, and arsenic have specific heats of 0.128, 4.18, 0.706, and .329 J g⁻¹ºC⁻¹, respectively. Which of the following would need the smallest quantity of heat to change the temperature of 5 g by 10ºC?
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The formula weight of a substance is
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To prepare 500 ml of 0.5 M NaCl from a stock of 2.0 M NaCl one needs to
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Which of the following salts is soluble in water?
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1.00 molal solution of NaCl in water contains
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A 3.17 m solution of CaCl₂ in water has a density of 1.24 g/mL. What is the molarity?
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A precipitate is expected when an aqueous solution of potassium iodide is added to an aqueous solution of
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According to avodgadro's law, the volume of a gas
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According to valence bond theory, which (specific) orbitals overlap in the formation of the bond in Cl₂?
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An unknown gas effuses 2.3 times faster than N₂O₄ at the same temperature. What is the identity of the unknown gas?
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Complete the following statement: In Charles' law, the volume of a gas _________ when the ________ decreases.
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Gases tend to behave ideally at
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In Amonton's (Gay-Lussac's) law, the pressure of a gas increases due to an increase in temperature because
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The pressure exerted by a gas on its container is directly proportional to
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Two metals of equal mass with different heat capacities are subjected to the same amount of heat. Which undergoes the smallest change in temperature?
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What reagent would distinguish between Ba²⁺ and Pb²⁺?
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Which definition is INCORRECT?
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Which of the following compounds is the strongest Bronsted acid?
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Which of the following is evidence for a chemical reaction?
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Which of the following reaction best describes the dissolution of solid NaOH (s) in water?
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At STP how many liters of NH₃ can be produced from the reaction of 6.0 L of N₂ with 6.0 L of
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Which of the following compounds is soluble in water?
?????
The true volume of a particular real gas is larger than the calculated from the ideal gas equation. This occurs because the ideal gas equation does NOT correct for
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Which of the following has a standard enthalpy of formation of zero?
Ar (g)
Which of the following elements can form compounds with an expanded octet?
As
Which of the following elements is most likely to form a molecular structure that does not obey the octet rule?
B
If the following ion Ba²⁺, Cl⁻, K⁺, and SO₄²⁻ are placed in a test tube, teh precipitate formed is
BaSO₄
Name the produces of the incomplete combustion any hydrocarbon
CO + H₂O
Which of the following compounds is the strongest Bronsted base?
Ca(OH)₂
Which of the following is a characteristic of an ideal gas?
Collision between gas particles and perfectly elastic
Of the choices below, which would be the best for the lining of a take intended for use in storage of hydrochloric acid?
Copper
Which species functions as the oxidizing agent in teh following reduction-oxidation reaction Zn(s) + Cu²⁺ (aq) --> Cu(s) + Zn²⁺ (aq)
Cu²⁺ (aq)
The empiracle formula of a compound is CH₂O and its molar mass is about 180g. What is its molecular formula?
C₆H₁₂O₆
Which is expected to have the largest dispersion forces?
C₈H₁₈
Which of the following could be an empirical formula?
C₉H₈O₄ (asprin)
Subtracting the vapor pressure of water from the total pressure of a gas collected over water is an example of the application of
Dalton's law
_____________ is the mesure of polarity of a chemical bond
Dipole moment
Which is the measure of the sum of the kinetic and potential energies of each particle in the system?
E, the internal energy
Of the following, which one is a state function?
H
Which of the following molecules is polar
H F \ / C = C / \ H F
Choose the bond below that is most polar
H-F
Which of the following compounds is a weak acid in an aqueous solution?
H₃PO₄
Which of the following is a statement of Hess's law?
If a reaction is carried out in a series of steps, the 𝚫H for the reaction will equal the sum of the enthalpy changes for the individual steps.
___________ are compounds with the same molecular formula but different structural formulas.
Isomers
In the neutralization reaction of acetic acid with aqueous lithium hydroxide, what is the spectator ion?
Li⁺ (aq)
The oxidation number of chlorine is highest in which of the following?
NaClO₃
Which of the following exhibits ionic bonding?
Na₂S
What ion is provided when Arrhenius bases dissolve in water?
OH⁻
What is the main difference between an ionic and a covalent bond
One is the sharing of a pair of electrons, the other is the transfer of at least one electron
Which species functions as the reducing agent in the following reduction-oxidation reaction 2P (s) + 3Br₂ (l) --> 2PBr₃ (l)
P (s)
Determine the empirical formula for a compound that is found to contain 10.14 mg P and 34.85 mg Cl.
PCl₃
In a single replacement reaction, why will one metal replace another metal in an ionic compound?
The metal will replace another metal if it can lose electrons more readily than the other metal.
How do atoms ahieve noble-gas electron configurations in single covalent bonds?
Two atoms share two electrons
VESPR stands for
Valence-Shell Electron-Pair Repulsion
What is a molecule
a group of atoms that are held together by covalent bonds
Which of the following statements best describes an ionic bond?
a strong lattic of positively and negatively charged atoms held together by electrical forces
The reatcion HNO₃ (aq) + KOH (aq) --> KNO₃ (aq) + H₂O (l) is best classified as a(n)
acid-base neutralization reaction
The heat capacity of an object depends on which of the following
all of the above
According to VB theory, sigma bonds are:
always present in triple bonds
An expanded octet may occur
anywhere in the 3rd period and below
Gaseous mixtures
are all homogeneous
In a molecule with covalent bonding
atoms are held together by sharing electrons
The octet rule indicates that
atoms lose, gain, or share valence electrons to have 8 valence electrons
which of the following is least likely to form multiple (double or triple) bonds
barium
The molecular geometry of H2O is
bent
Which process absorbs energy?
bond breaking
Which process releases energy
bond formation
If the products have a higher energy than the reactants
both B and C (the reaction is endothermic and the reactants have less energy than the products)
For the molecule H H | | — H— C = C — O — H —
both carbons are sp² hybridized
The followign reaction is an example of a _______ reaction 2C₂H₆ (g) + 7O₂ (g) --> 4CO₂ (g) + 6H₂O (g)
combustion
A chemical bond for which one of the bonded atoms provides both electrons for the bond is referred to as a:
coordinate covalent bond
As the number of covalent bonds between two atoms increases, the distance between the atoms ___________ and the strength of the bond between them ____________.
decreases increases
The mixing of idfferent gases by random molecular motion with frequent collisions is called
diffusion
The forces between polar molecules is known as
dipole-dipole forces
Which of the following best describes all the intermolecular forces exhibited by a pure sample of PH₃?
dispersion and dipole-dipole
What is the name of the intermolecular force caused by an instantaneous dipole in the particles?
dispersion force
A process by which gas molecules escape through a tiny hole in a membrane into a vacuum without collisions called
effusion
The basis of the VESPR model of molecular bonding is
electron domains in the valence shell of an atom will arrange themselves so as to minimize repulsions
Which of the following statements concerning ionic compounds is true?
essentially all ionic compounds are solids at room temperature and pressure
A chemical reaction that releases heat to the surroundings is said to be_____ and has a _________ 𝚫H at constant pressure.
exothermic, negative
When four atomic orbitals are mixed to form hybrid orbitals, how many hybrid orbitals are formed?
four
Molecules with an odd number of valence electrons and have at least one unpaired are called _____________
free radicals
Oxidation is the ________ and reduction is the _________.
gain of electrons loss of electrons
An ionic compound
has a net charge of zero
A σ bond:
has high electron probability along the axis between atoms
A real gas will behave most like an ideal gas under conditions of
high temperature and low pressure
What is the strongest type of intermolecular force present in NH₂CH₃?
hydrogen bonding
Consider a bond A-B. if the difference in electronegativity is 3.5, the bond is considered
ionic
The internal energy of a system
is the sum of the potential and kinetic energies of the components
Molality is defined as moles of solute per
kilogram of solvent
In a Lewis Structure, the central atom is typicallly the atom with the ____________.
least EN
When at atom in a molecule or ion is described as sp hybridized, its electron pair geometry is
linear
Molarity is defined as moles of solute per
liter of solution
An instrument used ot measure the pressure of a gas in a laboratory is called a
manometer
In ionic compounds, _______ lose the valence electrons to form positively charged _________.
metals cations
Which one of the following concentration units varies with temperature?
molarity
the molairty (M) of a solution refers to
moles of solute/L of solution
In the kinetic molecular theory of gas behavior, the assumption is made that gas moelcules
move rapidly in random directions
Which of the following compounds are the products of Ag + Li₂SO₄ -->
no reaction
Consider a bond A-B. If the difference in electronegativity is 0.0, the bond is considered
non polar covalent
With which of the following with the ammonium ion form an insoluble salt?
none of the above
The type of compound that is most likely to contain a covalent bond is
one composed of only nonmetals
To form a molecule with a tetrahedral electron domain geometry, what set of pure atomic orbitals must be mixed?
one s and three p
According to VB theory, a double bond that results from the sharing of four electrons consists of:
one sigma and one pi bond
The side-by-side overlap of p orbitals produces what kind of bond?
pi bond
Which of the following bond types is normally the weakest?
pi bond formed by overlap of two p orbitals
Resonance structures differ by
placement of electrons only
Consider a bond A-B. If the difference in electronegativity is 1.0, the bond is considered
polar covalent
A group of covalently bonded atoms that has an overall electrical charge is called a(n)
polyatomic ion
A _________𝚫H corresponds to an ________ process.
positive, endothermic
The reaction Na₃PO₄ (aq) + 3AgNO₃ (aq) --> Ag₃P (s) + 3NaNO₃ (aq) is best classified as a(n)
precipitation reaction
The force of gas particles against the walls of a container is called
pressure
When drawing the three-dimensional structure diagram of a molecule the wedge
shows a bond that projects out from the page.
Electrons in ____________ bonds remain localized between two atoms. Electrons in ____________ bonds can become delocalized between more than two atoms.
sigma, pi
The process of solute particles being surrounded by solvent particles is known as
solvation
The hybridization of the carbon atom labeled with ( ) in the molecule below is ____________. H H :O: | | || H—N—C—(C)—Ö—H | H—C—H | H
sp²
The hybridization of the oxygen atom labeled x in the structure below is ________. H H(:O:) | | || H—N—C—C—O—H | H—C—H | H
sp²
What orbital hybridization is expected for the central aotm in a molecule with a trigonal planar geometry?
sp²
Which orbital hybridization is associated with a tetrahedral electron domain arrangement?
sp³
The electron-domain geometry of the AsF₅ molecule is trigonal bipyramidal. The hybrid orbitals used by the As atom for bonding are __________ orbitals.
sp³d
What combination of hybrid orbital descriptions and electronic geometry descriptions is INCORRECT?
sp³d/square planar
According to the Dalton's law of partial pressures, the total pressure of a mixture of ideal gases is equal to the
sum of the partial pressures
In a _________ reaction, two or more elements or compounds form one product.
synthesis
The molecular geometry of the left-most carbon atom in the molecule below is H O | || H—C—C—O—H | H
tetrahedral
During the process of diluting a solution to a lower concentratin
the amount of solute does not change
What is shown by the structural formula of a molecule?
the arrangement of bonded atoms
Formal charge is
the difference between the number of valence electrons in a free atom and the number of electrons assigned to the atom in a Lewis structure
For the molecule |O| H || | H— C — N — H —
the hybridization for C is sp³
The chemical formula of an ionic compound shows
the lowest whole-number ratio betweens ions in the ionic compound
A solute is
the material that dissolves in the solvent portion of a solution.
Which of the following statements concerning real gases is/are CORRECT?
the molecules in a real gas are attracted to each other
A chemical equation is balanced when
the number of atoms of each elemtn is the same in reactants and products
A disproportionation reaction is one in which
the same substance is both oxidized and reduced
Enthalpy is defined as
the sume of the internal energy and the pressure-volume product of a system
Which one of the following conditions would always result in an increase in the internal energy of a system?
the system gains heat and has work done on it by the surroundings.
What information does a molecular formula provide?
the type and number of atoms present in the molecule
The electron-domain geometry and the molecular geometry of a molecule of the general formula ABⁿ will always be the same if
there are no lone pairs on the central atom
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
they have a great tendency to lose electrons
The hybridization of orbitals on the central atom in a molecule is sp². The electron-domain geoemetry about this central atom is ____________.
trigonal planar
A triple bond is generally composed of
two π bonds and one σ bond
The description of covalent bond formation as a region of high electronic charge density resulting from overlap of atomic orbitals between the two bonded atoms is referred to as
valence bond theory
Which of the following are the same for each gas in a mixture of gases that are confined in a single vessel?
volume and temperature
A neutralization reaction between an acid and a metal hydroxide produces ________.
water and a salt
What happens to the value of 𝚫H for a thermochemical reaction if the reaction is reverse
𝚫H has the same numerical value, and sign change
What is the oxidation number of the sulfur atom in H₂SO₄?
+2
What is the oxidation number of the chromium atom in K₂Cr₂O₇?
+6
What is the total mass of solute in 1000 g of a solution having a concentration of 5 parts per million
.005 g
The formal charge of carbon the molecule below is ․․ ․․ O = C = O ․․ ․․
0
What is the oxidation number of the sulfur atom in S₈?
0
