General Chemistry 112 Exam 2 Chapters 17, 19, 20

Front 1

In a solution, when the conentrations of a weak acid and its conjugate base are equal,

A.) the -log of the [H+] and the -log of the Ka are equal
B.) the buffering capacity is significantly decreased
C.) the system is not at equilibrium
D.) all of the above are true

Back 1

A.) the -log of the [H+] and the -log of the Ka are equal

Front 2

The addition of hydrofluoric acid and __________ to water producers a buffer solution.

A.) HCl
B.) NaBr
C.) NaNO3
D.) NaF
E.) NaCl

Back 2

D.) NaF

Front 3

In which of the following aqueous solutions would you expect AgBr to have the highest solubility?

A.) 0.10M AgNO3
B.) 0.20M NaBr
C.) pure water
D.) 0.15M KBr
E.) 0.10M LiBr

Back 3

C.) pure water

Front 4

A reaction that is spontaneous as written _______

A.) will proceed without outside intervention
B.) is very slow
C.) has an equilibrium position that lies far to the left
D.) is also spontaneous in the reverse direction
E.) is very rapid

Back 4

A.) will proceed without outside intervention

Front 5

The Henderson-Hasselbalch equation is _________:

A.) pH=pKa - log [base]/[acid]
B.) pH = pKa + log [acid]/[base]
C.) pH = log [acid]/[base]
D.) pH = pKa + log [base]/[acid]
E.) [H+] = Ka + [base]/[acid]

Back 5

D.) pH = pKa + log [base]/[acid]

Front 6

The first law of thermodynamics can be given as __________.

A.) deltaE = q+w
B.) the entropy of a pure crystalline substance at absolute zero is zero
C.) forany spontaneous process, the entropy of the universe increases
D.) deltaHrxn = ndeltaHf(products)-mdeltaHf(reactants)
E.) deltaS = qrev/T at constant temperature

Back 6

A.) deltaE = q+w

Front 7

_______ is the oxidizing agen in the reaction below.

Cr2O7(2-) + 6S2O3(2-) +14H(+) --> 2Cr(3+) + 3S4O6(2-) + 7H2O

A.) S2O3 (2-)
B.) Cr(3+)
C.) Cr2O7(2-)
D.) S4O6(2-)

Back 7

C.) Cr2O7(2-)

Front 8

when a system is at equilibrium, ___________

A.) the reverse process is spontaneous but the forward process is not
B.) the forward process is spontaneous but the reverse process is not
C.) both forward and reverse processes have stopped
D.) the forward and reverse processes are both spontaneous
E.) the process is not spontaneous in either direction

Back 8

E.) the process is not spontaneous in either direction

Front 9

The thermodynamic quantity that expresses the degree of disorder in a system is _________.

A.) entropy
B.) enthalpy
C.) heat flow
D.) internal energy
E.) bond energy

Back 9

A.) entropy

Front 10

The gain of electrons by an element is called ________.

A.) fractionation
B.) reduction
C.) sublimation
D.) oxidation
E.) disproportionation

Back 10

B.) reduction

Front 11

The entropy of the universe is ________.

A.) zero
B.) the same as the energy, E
C.) continually decreasing
D.) constant
E.) continually increasing

Back 11

E.) continually increasing

Front 12

The second law of thermodynamics states that ________.

A.) deltaE = q+w
B.) deltaS = qrev/T at constant temperature
C.) the entropy of a pure crystalline substance at absolute zero is zero
D.) deltaHrxn = ndeltaHf(products)-mdeltaHf(reactants)
E.) for any spontaneous process, the entropy of the universe increases

Back 12

E.) for any spontaneous process, the entropy of the universe increases

Front 13

What is the oxidation number of bromine in the BrO3 (-) ion?

A.) +1
B.) +7
C.) +5
D.) +3
E.) -1

Back 13

C.) +5

Front 14

In a voltaic cell, electrons flow from the _____ to the _______.

A.) salt bridge, anode
B.) anode, cathode
C.) cathode, anode
D.) salt bridge, cathode
E.) anode, salt bridge

Back 14

B.) anode, cathode

Front 15

1V = _______.

A.) 1 J/s
B.) 96485 C
C.) 1 J/C
D.) 1 amp*s
E.) 1 C/J

Back 15

C.) 1 J/C

Front 16

The relationship between the change in Gibbs free energy and the emf of an electrochemical cell is given by ______.

A.) delta G = -E/nF
B.) delta G = -nF/E
C.) delta G = -nFE
D.) delta G = -nF/ERT
E.) delta G = -nRTF

Back 16

C.) delta G = -nFE

Front 17

Delta S is positive for the reaction _______.

A.) CO2 (g) --> CO2 (s)
B.) BaF2 (s) --> Ba (2+) (aq) + 2F(-) (aq)
C.) 2Hg (l) + O2 (g) --> 2HgO (s)
D.) 2NO2 (g) --> N2O4 (g)
E.) 2H2 (g) + O2 (g) --> 2H2O (g)

Back 17

B.) BaF2 (s) --> Ba (2+) (aq) + 2F(-) (aq)

Front 18

One of the differences between a voltaic cell and an electrolytic cell is that an electrolytic cell ____.

A.) a nonspontaneous reaction is forced to occur
B.) oxidation occurs at the cathode
C.) electrons flow toward the anode
D.) an electric current is produced by a chemical reaction
E.) O2 gas is produced at the cathode

Back 18

A.) a nonspontaneous reaction is forced to occur

Front 19

Which one of the following processes produces a decrease in the entropy of the system?

A.) boiling water to form steam
B.) melting ice to form water
C.) freezing water to form ice
D.) dissolution of solid KCl in water
E.) mixing of two gases into one container

Back 19

C.) freezing water to form ice

Front 20

Which one of the following correctly indicates the relationsihip between the entropy of a system and the number of different arrangements, W, in the system?

A.) S = kW
B.) S = k/W
C.) S = k lnW
D.) S = Wk
E.) S = W/k

Back 20

C.) S = k lnW

Front 21

The purpose of the salt bridge in an electrochemical cell is to ______.

A.) maintain electrical neutrality in the half-cells via migration of ions.
B.) provide a means for electrons to travel from the cathode to the anode
C.) provide a means for electrons to travel from the anode to the cathode
D.) provide a source of ions to react at the anode and cathode
E.) provide oxygen to facilitate oxidation at the anode

Back 21

A.) maintain electrical neutrality in the half-cells via migration of ions

Front 22

In the formula delta G = -nFE, F is the ______.

Back 22

Faraday constant

Front 23

In general, the solubility of a slightly soluble salt is ________ by the presence of a second solute that furnishes a common ion.

Back 23

decreased

Front 24

Processes that are spontaneous in one direction are nonspontaneous in the _______ direction.

Back 24

reverse

Front 25

Entropy _____ as the number of microstates in the system increases.

Back 25

increases

Front 26

The most difficult a species is to reduce and the poorer an ________ agent is it.

Back 26

oxidizing

Front 27

The phrase "like dissolves like" refers to the fact that ____.

A.) solvents can only dissolve solutes of similar molar mass
B.) polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes
C.) condensed phases can only dissolve other condensed phases
D.) polar solvents dissolved nonpolar solutes and vice versa
E.) gases can only dissolve other gases

Back 27

B.) polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes

Front 28

A solution with a concentration higher than the solubility is ______.

A.) is unsaturated
B.) is not possible
C.) is supercritical
D.) is saturated
E.) is supersaturated

Back 28

E.) is supersaturated

Front 29

Molality is defined as the _____.

A.) moles solute/Liters solution
B.) moles solute/ moles solvent
C.) moles solute/ kg solvent
D.) moles solute/ kg solution
E.) none (dimensionless)

Back 29

C.) moles solute/kg solvent

Front 30

The process of solute particles being surrounded by solvent particles is known as ______.

A.) salutation
B.) solvation
C.) agglomeration
D.) dehydration
E.) agglutination

Back 30

B.) solvation

Front 31

Formation of solutions where the process is endothermic can be spontaneous provided that ______.

A.) they are accompanied by another process that is exothermic
B.) the solvent is a gas and the solute is a solid
C.) they are accompanied by an increase in order
D.) the solvent is water and the solute is a gas
E.) they are accompanied by an increase in disorder

Back 31

E.) they are accompanied by an increase in disorder

Front 32

The rate law for a reaction is:

rate = k[A][B]2

Which one of the following statements is false?

A.) the reaction is second order overall
B.) k is the reaction rate constant
C.) if [B] is doubled, the reaction rate will increase by a factor of 4
D.) the reaction is first order in A
E.) the reaction is second order in B

Back 32

A.) the reaction is second order overall

Front 33

The rate law of the overall reaction

A + B --> C

is rate = k[A]2. Which of the following will not increase the rate of the reaction?

A.) increasing the concentration of reactant A
B.) increasing the temperature of the reaction
C.) adding a catalyst for the reaction
D.) increasing the concentration of reactant B
E.) all of these will increase the rate

Back 33

D.) increasing the concentration of reactant B

Front 34

The mechanism for formation of the product X is:

A+B --> C + D (slow)
B + D --> X (fast)

The intermediate reactant in the reaction is _______.

A.) A
B.) B
C.) C
D.) D
E.) X

Back 34

D.) D

Front 35

At equilibrium, ___________.

A.) the rates of the forward and reverse reactions are equal
B.) the rate constants of the forward and reverse reactions are equal
C.) all chemical reactions have ceased
D.) the value of the equilibrium constant is 1
E.) the limiting reagent has been consumed

Back 35

A.) the rates of the forward and reverse reactions are equal

Front 36

Which of the following expressions is the corect equilibrium-constant expression for the equilibrium between dinitrogen tetroxide and nitrogen dioxide?

N2O4 (g) --> 2NO2 (g)

A.) [NO2]2/[N2O4]
B.) [NO2]/[N2O4]
C.) [NO2]2[N2O4]
D.) [NO2]/[N2O4]
E.) [NO2]/[N2O4]

Back 36

A.) [NO2]2/[N2O4]

Front 37

The equilibrium constant for the gas phase reaction

N2 (g) + 3H2 (g) <--> 2NH3 (g)

is Keq = 4.34*10^-3 at 300 degrees Celsius. At equilibrium, _____.

A.) only products are present
B.) products predominate
C.) reactants predominate
D.) roughly equal amounts of products and reactants are present
E.) only reactants are present

Back 37

C.) reactants predominate

Front 38

The equlibrium constant for the gas phase reaction

2NH3 (g) <--> N2 (g) + 3H2 (g)

is Keq = 230 at 300 degrees Celsius. At equilibrium, _____.

A.) only products are present
B.) reactants predominate
C.) products predominate
D.) roughly equal amounts of products and reactants are present
E.) only reactants are present

Back 38

C.) products predominate

Front 39

The reaction below is exothermic:

2SO2 (g) + O2 (g) <--> 2SO3 (g)

Le Chatelier's Principle predicts that _____ will result in an increase in the number of moles of SO3 (g) in the reaction container.

A.) increasing the volume of the container
B.) increasing the pressure
C.) removing some oxygen
D.) decreasing the pressure
E.) increasing the temperature

Back 39

B.) increasing the pressure

Front 40

The conjugate acid of HSO4 (-) is _____.

A.) HSO4 (+)
B.) SO4 (2-)
C.) H (+)
D.) HSO3 (+)
E.) H2SO4

Back 40

E.) H2SO4

Front 41

According to the Arrhenius concept, an acid is a substance that _____.

A.) tastes bitter
B.) reacts with the solvent to form the cation formed by autoionization of that solvent
C.) causes an increase in the concentration of H+ in aqueous solutions
D.) fan accept a pair of electrons to form a coordinate covalent bond
E.) is capable of donating one or more H+

Back 41

C.) causes an increase in the concentration of H+ in aqueous solutions

Front 42

A Bronsted-Lowry base is defined as a substance that _____.

A.) acts as a proton acceptor
B.) increases [H+] when placed in H2O
C.) decreases [H+] when placed in H2O
D.) increases [OH-] when placed in H2O
E.) acts as a proton donor

Back 42

A.) acts as a proton acceptor

Front 43

A Bronsted-Lowry acid is defined as a substance that ____.

A.) acts as a proton donor
B.) decreases [H+] when placed in H2O
C.) increases Ka when placed in H2O
D.) acts as a proton acceptor
E.) increases [OH-] when placed in H2O

Back 43

A.) acts as a proton donor

Front 44

A substance that is capable of acting as both an acid and as a base is _____.

A.) conjugated
B.) miscible
C.) amphoteric
D.) saturated
E.) autosomal

Back 44

C.) amphoteric

Front 45

Which solution below has the highest concentration of hydroxide ions?

A.) pH = 3.21
B.) pH = 12.6
C.) pH = 7.00
D.) pH = 7.93
E.) pH = 9.82

Back 45

B.) pH = 12.6

Front 46

An aqueous soltuion contains 0.10M NaOH. The solution is _____.

A.) basic
B.) very dilute
C.) acidic
D.) neutral
E.) highly colored

Back 46

A.) basic

Front 47

Nitric acid is a strong acid. This means that _____.

A.) aqueous solutions of HNO3 contain equal concentrations of H+ (aq) and OH- (aq)
B.) HNO3 cannot be neutralized by a weak base
C.) HNO3 dissociates completely to H+ (aq) and NO3- (aq) when it dissolves in water
D.) HNO3 produces a gaseous product when it is neutralized
E.) HNO3 does not dissociate at all when it is dissolved in water

Back 47

C.) HNO3 dissociates completely to H+ (aq) and NO3- (aq) when it dissolves in water

Front 48

Of the following, ___ is a weak acid.

A.) HF
B.) HClO4
C.) HCl
D.) HBr
E.) HNO3

Back 48

A.) HF

Front 49

The pH is defined as ________.

A.) -log[OH-]
B.) -log[Ka]
C.) -log[Kb]
D.) -log[H+]

Back 49

D.) -log[H+]

Front 50

Physical properties of a solution that depend on the quantity of the solute particles present, but not the kind or identity of the particles, are termed ____ properties.

Back 50

colligative

Front 51

If a rate law is second order (reactant), doubling the reactant _____ the reaction rate.

Back 51

quadrupling

Front 52

The minimum energy to initiate a chemical reaction is the _______.

Back 52

activation energy

Front 53

Pure _____ and pure _____ are excluded from equilibrium-constant expressions.

Back 53

solids
liquids

Front 54

If the value for the equilibrium constant is much greater than 1, then the equilibrium mixture contains mostly _____.

Back 54

products