Deck 17: Electrochemistry the Quest for Clean Energy

Question 1

A voltaic cell is constructed based on the reaction of Ni (s) with Cu²⁺(aq) producing Ni²⁺(aq) and Cu(s).Identify the correct cell diagram.

A)Ni²⁺(aq), Cu²⁺(aq) || Nis) | Cus)
B)Ni(s) | Ni²⁺(aq) || Cu²⁺(aq) | Cu(s)
C)Ni(s) | Cu²⁺(aq) || Ni²⁺(aq) | Cu(s)
D)Cu²⁺(aq) | Cu(s) || Ni(s) | Ni2+(aq)
E)Cu(s) | Cu²⁺(aq) || Ni²⁺(aq) | Nis)

Answer 1

Ni(s) | Ni²⁺(aq) || Cu²⁺(aq) | Cu(s)

Question 2

Glancing at a periodic table, where do you expect to find elements that are good reducing agents?

A)in groups 16 and 17
B)on the left
C)in the middle
D)at the bottom
E)in group 17

Answer 2

on the left

Question 3

Reduction refers to

A)loss of mass.
B)an increase in oxidation number.
C)a decrease in oxidation number.
D)a decrease in the atomic number.
E)a gain in the number of protons.

Answer 3

a decrease in oxidation number.

Question 4

Which statement below regarding voltaic cells is FALSE?

A)Reduction occurs at the cathode.
B)Anions move through the barrier or bridge toward the electrode where oxidation is occurring.
C)The electrode where reduction is occurring is represented by a positive sign.
D)Electrons flow in the external circuit from the cathode to the anode.
E)Electrons flow in the external circuit toward the electrode represented by a positive sign.

Question 5

A voltaic cell is constructed based on the reaction of Br ^-(aq) with Cl₂(g) producing Cl^-0(g) and Br₂(l ), with platinum serving as inert electrodes.Identify the correct cell diagram.

A)Br₂(l ) | Br ^-(aq) || Cl₂(g) | Cl^-(aq)
B)Pt(s) | Cl₂(g) | Cl^-(aq) || Br₂(l ) | Br ^-(aq) | Pt(s)
C)Pt(s) | Br ^-(aq) | Cl₂(g) || Br₂(l ) | Cl^-(aq) | Pt(s)
D)Pt(s) | Br ^-(aq) | Br₂(l ) || Cl₂(g) | Cl^-(aq) | Pt(s)
E)Pt(s) | Br₂(l ) | Br ^-(aq) || Cl₂(g) | Cl^-(aq) | Pt(s)

Question 6

Use the table of standard reduction potentials below to identify the species that is the strongest reducing agent.

A)Pb⁴⁺
B)PB^₂+
C)K⁺
D)K
E)Al

Question 7

Which statement below about a voltaic cell is FALSE?

A)Usually the cathode is a metal strip.
B)Reduction occurs at the cathode.
C)Electrons are produced at the cathode.
D)In the external circuit, electrons flow toward the cathode.
E)Chemical species can have their oxidation number decreased at the cathode.

Question 8

Oxidation refers to

A)an increase in oxidation number.
B)a decrease in oxidation number.
C)a gain in the number of protons.
D)an increase in the atomic number.
E)an increase in mass.

Question 9

Which one of the following items does NOT characterize a reducing agent?

A)A reducing agent loses electrons.
B)A reducing agent causes another species to be reduced.
C)The oxidation number of a reducing agent increases.
D)A good reducing agent is a metal in a high oxidation state, such as Mn7+.
E)An example of a good reducing agent is an alkali metal, such as Na.

Question 10

Reduction is the

A)gain of electrons.
B)loss of electrons.
C)gain of protons.
D)loss of protons.
E)loss of mass.

Question 11

In the smelting of iron from iron oxide according to the equation Fe₂O₃ (s) + 3 CO(g) $\rightarrow$ 2 Fe(s) + 3 CO₂ (g), what is the change in oxidation number for iron?

A)(+3)
B)(+2)
C)0
D)(-2)
E)(-3)

Question 12

A voltaic cell is constructed based on the reaction of Ag(CN)₂^-(aq) with Cr(s) producing Ag(s) and Cr³⁺(s).Identify the correct cell diagram.

A)Ag(CN)₂^-(aq) | Cr(s) || Ag(s) | Cr³⁺(aq)
B)Ag(s) | Cr³⁺(aq) || Ag(CN)₂^-(aq) | Cr(s)
C)Cr(s) | Cr³⁺(aq) || Ag(s) | Ag(CN)₂^-(aq)
D)Ag(CN)₂^-(aq) | Ag(s) || Cr(s) | Cr³⁺(aq)
E)Cr(s) | Cr³⁺(aq) || Ag(CN)₂^-(aq) | Ag(s)

Question 13

Based on the cell diagram, Fe(s) | Fe^₂+(aq) || O₂(g) | H⁺(aq) | H₂O(l ) | Pt(s), which statement below is FALSE?

A)Fe is oxidized at the anode.
B)O₂ is reduced at the cathode.
C)H⁺ is oxidized at the anode.
D)Four moles of electrons are transferred in the balanced redox reaction.
E)The reaction occurs under acidic conditions.

Question 14

Proteins containing a certain functional group (identified as RSH) can be titrated with a triiodide ion to produce another functional group (identified as RSSR).The reaction equation is given below.What is oxidized and what is reduced in this reaction? 2 RSH(aq) +I₃^-(aq) $\rightarrow$ 3I^-(aq) + RSSR(aq) +2H⁺(aq)

A)RSH is oxidized; I₃^- is reduced.
B)RSH is reduced; I is oxidized.
C)Both RSH and I are oxidized.
D)Both RSH and I are reduced.
E)This reaction is not oxidation-reduction.

Question 15

Where on the periodic table do you expect to find elements that have high reduction potentials?

A)on the right except for the last group)
B)in the middle left
C)in the top left
D)at the bottom
E)in the transition metals

Question 16

Which statement below about a cathode in a voltaic cell is FALSE?

A)Oxidation occurs at the cathode.
B)Reduction occurs at the cathode.
C)Usually the cathode is a metal strip.
D)In the external circuit, electrons flow toward the cathode.
E)Chemical species can have their oxidation number decreased at the cathode.

Question 17

Glancing at a periodic table, where do you expect to find elements that are good oxidizing agents?

A)at the bottom left
B)in the top left
C)in the transition metals
D)at the bottom
E)on the right except for the last group)

Question 18

Oxidation is the

A)gain of electrons.
B)loss of electrons.
C)gain of protons.
D)loss of protons.
E)loss of mass.

Question 19

What is the oxidation number of sulfur in the ionic compound ammonium disulfate, (NH₄)₂S₂O₇?

A)(+3)
B)(+4)
C)(+5)
D)(+6)
E)(+7)

Question 20

Consider the reaction, Sn + Au^{3 +} $\rightarrow$ Sn^{2 +} + Au.Which of the following is NOT correct?

A)The oxidation half-reaction is Sn $\rightarrow$ Sn^{2 +} +2e^-.
B)The reduction half-reaction is Au^{3 +}+3e⁺ $\rightarrow$ Au.
C)Au³⁺ is the oxidizing agent.
D)The equation is balanced as written.
E)More than one statement is not correct.

Question 21

Using the following data, determine E^o_cell for the electrochemical cell constructed using the reaction of nitrous oxide and oxalic acid under acidic conditions.Unbalanced: N₂O(g) + H₂C2O₄( s) $\rightarrow$ 2 CO₂ (g)+N₂ (g) +H₂ O(l)

A)(+1.29 V)
B)(-1.29 V)
C)(+2.27 V)
D)(-2.27 V)
E)(+0.87 V)

Question 22

If the potential of a voltaic cell is +1.20 V, what is the free-energy change when one mole of electrons is transferred in the oxidation-reduction reaction?

A)(+116 kJ)
B)(-116 kJ)
C)(-1.20 kJ)
D)(-1.20 kJ).
E)(+602 kJ)

Question 23

Which statement below regarding reduction potentials is FALSE?

A)Higher reduction potentials are associated with stronger reducing agents.
B)As reduction potential increases, the ease of reduction increases.
C)A substance with a higher reduction potential will oxidize a substance with a lower reduction potential.
D)Metals such as sodium and potassium are strong reducing agents.
E)Standard reduction potentials are measured relative to the reduction of H ⁺ aq) to H₂g).

Question 24

Which one of the following items does NOT characterize an oxidizing agent?

A)An oxidizing agent has a high reduction potential.
B)An oxidizing agent causes another species to be oxidized.
C)An oxidizing agent gains electrons in a redox reaction.
D)A good oxidizing agent is a metal in a high oxidation state, such as MnVII).
E)An example of a good oxidizing agent is an alkali metal, such as Na.

Question 25

The work involved in moving exactly 1 mole of electrons through a potential difference of exactly 1 V is

A)1 J.
B)1 kJ.
C)96.5 J.
D)6.02 kJ.
E)96.5 kJ.

Question 26

Using the following data, determine the standard cell potential E^o _cell for the electrochemical cell constructed using the following reaction: Mn(s) + Cd²⁺(aq) $\rightarrow$ Mn²⁺(aq) + Cd(s).

A)(+.782 V)
B)(-0.782 V)
C)(+1.967 V)
D)(-1.588 V)
E)(+1.588 V)

Question 27

Which statement below regarding chemical energy and electrical work is FALSE?

A)The amount of work available from an electrochemical cell is independent of the amounts of reactants present.
B)The amount of charge transferred in an electrochemical cell is directly proportional to the electrical work the cell performs.
C)When the free energy of an electrochemical cell decreases, the cell potential is positive.
D)The amount of work done by an electrochemical cell depends on the amount of charge transferred.
E)As cell potential increases, the amount of work available increases.

Question 28

Using the following data, determine the standard cell potential E^o _cell for the electrochemical cell constructed based on the following unbalanced reaction expression:

A)(-1.385 V)
B)(+1.385 V)
C)(+1.939 V)
D)(-2.770 V)
E)(+2.770 V)

Question 29

Use the table of standard reduction potentials below to identify the species that is the strongest oxidizing agent.

A)Pb⁴⁺
B)PB^₂+
C)K⁺
D)K
E)Al

Question 30

What is the standard cell potential for a voltaic cell using the Pb 2+/Pb and Mg2+/Mg half-reactions? Which metal is the cathode?

A)(-2.25 V, Pb is the cathode)
B)(+2.49 V, Mg is the cathode)
C)(+2.25 V, Mg is the cathode)
D)(+2.25 V, Pb is the cathode)
E)(-2.49 V, Mg is the cathode)

Question 31

Use the table of standard reduction potentials below to identify which statement below is FALSE.

A)Pb4+will oxidize all of the species on the right side of the arrows in the other half-reactions.
B)K will reduce all of the species on the left side of the arrows in the other half-reactions.
C)I₂ is a better reducing agent than PB₂+.
D)Al is easier to oxidize than Fe.
E)Mg is a better reducing agent than Pb.

Question 32

The bromate ion, BrO₃-, can form in drinking water if ozone disinfection is performed under basic conditions when bromide ions are present.If this redox reaction were performed in an electrochemical cell, what would the standard cell potential be? The relevant reduction reactions and standard reduction potentials are given below.
BrO₃-+ 3 H₂O + 6 e- $\rightarrow$ Br -+ 6 OH^- $\quad$ +0.58 V
O₃ + H₂O + 2 e- $\rightarrow$ O₂+ 2 OH^- $\quad$$\quad$$\quad$ ++1.24 V

A)(-3.14 V)
B)(+3.14 V)
C)(+1.05 V)
D)(+1.82 V)
E)(+0.66 V)

Question 33

Silver tarnish Ag₂S) can be removed by immersing silverware in a hot solution of baking soda NaHCO₃) in a pan lined with aluminum foil; however, foul-smelling hydrogen sulfide gas H₂S) is produced.Which of the statements below is true?

A)Aluminum ions react with S²⁺, form aluminum sulfide, and gaseous carbon dioxide is released.
B)Silver ions in the presence of the baking soda NaHCO₃) oxidize sulfide to elemental sulfur that attacks the aluminum foil, which produces aluminum sulfide.
C)The aluminum acts as a reducing agent for the silverI) in silver sulfide; then bicarbonate ion protonates the sulfide ion that is released.
D)Aluminum is plated onto the silver surface, making it shiny again, and then the reaction of bicarbonate with aluminum oxide releases CO₂.
E)Silver in Ag₂S reduces the aluminum, becomes metallic silver in the process, and releases hydrogen sulfide, H₂S.

Question 34

The magnitude of the charge on a mole of electrons is

A)1 C.
B)9.65 C.
C)9.65 * 104 C.
D)6.02 * 1023 C.
E)9650 C.

Question 35

Silver tarnish( Ag₂S) can be removed by immersing silverware in a hot solution of baking soda( NaHCO₃) in a pan lined with aluminum foil; however, foul-smelling hydrogen sulfide gas (H₂S) is produced.What is E^o _cell for the redox reaction that occurs?

A)(+3.512 V)
B)(+1.051 V)
C)(+2.461 V)
D)(+1.521 V)
E)(+0.940 V)

Question 36

In one episode of the 1960s television sitcom, Gilligan's Island, the famous "professor" constructed voltaic cells to use as substitutes for their radio's dead batteries.A single D-cell has an emf of 1.5 V.Which scraps of metal from their damaged boat, the Minnow, could best be used to create a 1.5 V voltaic cell? Assume that coconuts make great beakers and that seawater is a terrific electrolyte.

A)silver anode and lead cathode
B)aluminum anode and lead cathode
C)iron anode and aluminum cathode
D)aluminum anode and silver cathode
E)lead anode and silver cathode

Question 37

The spontaneous redox reaction in a voltaic cell has a

A)negative value of E_cell and a negative value of $\Delta$ G.
B)positive value of E_cell and a positive value of $\Delta$ G.
C)negative value of E_cell and a positive value of $\Delta$ G.
D)positive value of E_cell and a negative value of $\Delta$ G.
E)positive value of E_cell and a value of zero for $\Delta$ G.

Question 38

Silver tarnish (Ag₂S) can be removed by immersing silverware in a hot solution of baking soda (NaHCO₃) in a pan lined with aluminum foil; however, foul-smelling hydrogen sulfide gas (H₂S) is produced.Which one of the following reactions does NOT represent part or all of what is happening?

A)Al $\rightarrow$ Al³⁺+10 3e^-
B)Ag⁺+e^- $\rightarrow$ Ag
C)2 HCO ^- +S^{2 -} $\rightarrow$ H S +2 CO ^{2 -} 3 2 3
D)3Ag₂S+ 2 Al+ 3 H₂O $\rightarrow$ 6 Ag +AL₂O₃ + 3 H₂S
E)2 HCO₃^-+Ag₂S $\rightarrow$ H₂S+ 2 CO₃^2- + 2 Ag

Question 39

Based on the information in the table of standard reduction potentials below, what is the standard cell potential for an electrochemical cell that has iron Fe) and magnesium Mg) electrodes immersed in 1M Fe3+and Mg2+solutions? Also, identify the cathode.

A)(+1.60 V with Fe as the cathode)
B)(-1.60 V with Mg as the cathode)
C)(-3.14 V with Fe as the cathode)
D)(-3.14 V with Mg as the cathode)
E)(+3.14 V with Fe as the cathode)

Question 40

Identify the strongest reducing agent in the following half-reactions.The standard reduction potentials are listed.

A)Cr
B)MnO₂
C)Hg₂SO₄
D)Sn
E)Hg

Question 41

An electronic device requires two 1.50-V AA zinc-carbon batteries, which, connected in series, give 3.00 V.If the cell transfers two moles of electrons for each mole of reaction, how much electrical work can be performed by the batteries?

A)5.79*10² kJ
B)4.34* 10² kJ
C)8.69 * 10² kJ
D)2.90 *10² kJ
E)72.4 kJ

Question 42

What is the cell potential for an electrochemical cell at 298 K with a copper metal electrode immersed in a 2.0 *10^-3 M copper sulfate solution in one compartment and a copper metal electrode immersed in a 1.5 M copper sulfate solution in the other compartment?
(Cu²⁺0aq) +2e^- $\rightarrow$ Cus), E°=+0.342 V

A)(+0.342 V)
B)(+0.257 V)
C)(+0.085 V)
D)(F+0.427 V)
E)(+0.085 V).

Question 43

What is true when a battery voltaic cell) is dead?

A)E^o _cell = 0 and Q = K
B)E_cell =and Q = K
C)E_cell =and Q= 0
D)E^o _cell = 0 and Q =0 cell cell
E)E_cell =0 and K = 0

Question 44

The standard hydrogen electrode is

A)used to calibrate voltmeters.
B)the reference point for all standard reduction potentials.
C)needed to activate electrochemical cells.
D)often overlooked in measuring standard reduction potentials.
E)used to produce a standard cell potential of exactly 1 V.

Question 45

Calculate E_cell for an electrochemical cell based on the two half-reactions given below when the reaction occurs in an acidic aqueous solution in which the pH is buffered at 4.00 and [MnO₄-] = 1.80 M and [Fe²⁺] =0.0220 M.Use the smallest whole-number coefficients possible when
Balancing the overall reaction.

A)(+2.10 V)
B)(+0.964 V)
C)(+1.21 V)
D)(+1.86 V)
E)(+2.38 V)

Question 46

The Nernst equation can be used to calculate

A)standard cell potentials from standard reduction potentials.
B)the change in standard Gibbs free energy from standard cell potentials.
C)cell potentials from standard cell potentials when the conditions of concentration and temperature are not standard.
D)cell potentials given only the temperature and reactant concentrations.
E)cell potentials from standard oxidation potentials.

Question 47

An electrochemical cell is constructed with a zinc metal anode in contact with a 5.20*10^-2 M solution of zincII) nitrate and a silver cathode in contact with a 4.20 *10^-3 M solution of silverI) nitrate.What is the emf of this cell at 5°C?

A)1.656 V
B)1.609 V
C)1.561 V
D)1.370 V
E)1.458 V

Question 48

An electrochemical cell contains a standard hydrogen electrode and a cathode consisting of a metallic chromium electrode, Cr(s), in contact with a 1.00 M chromium solution, Cr³⁺(aq).The voltage produced by this cell was measured at 25°C.Which statements describe the results of this measurement, assuming the conditions are ideal? The cell voltage with the appropriate sign equals I.the cell potential.
II.the electromotive force.
III.the standard cell potential.
IV.the standard reduction potential for Cr³⁺/Cr.

A)I only
B)I and II
C)I, II, and III
D)I, II, III, and IV
E)III only

Question 49

An electronic device requires four 1.50-V AA alkaline batteries, which, connected in series, give 6.00 V.If the cell transfers two moles of electrons for each mole of reaction, what is the Gibbs free-energy change for the redox reaction in each of the batteries?

A)(-1.45 *10² kJ)
B)(+1.45 * 10² kJ)
C)(+5.79 *10² kJ)
D)(-8.69* 10² kJ)
E)(-2.90 * 10² kJ)

Question 50

Neuron cells generate electrical signals by concentration gradients across membranes.Assuming a potassium ion concentration of 0.00300 M inside the cell and a concentration of 0.135 M outside the cell, what is the electrical potential across the cell membrane? Body temperature is 310 K.The sign identifies the change in the electrical potential across the membrane and which way the ions flow.

A)(+2 mV)
B)(-136 mV)
C)(+.0 mV)
D)(-204 mV)
E)(+204 mV)

Question 51

Calculate $\Delta$ G for an electrochemical cell reaction that occurs under basic aqueous conditions based on the following two half-reactions for which the standard reduction potentials are given.Use the smallest whole-number coefficients possible when balancing the overall reaction.
Cd(OH)2 + 2e^- $\rightarrow$ Cd + 2 OH^- $\quad$$\quad$$\quad$$\quad$ -0.824 V
NiO(OH) + H₂ O +e^- $\rightarrow$ Ni(OH)2 +OH^- $\quad$ +1.32 V

A)(-669 kJ)
B)(+95.7 kJ)
C)(-95.7 kJ)
D)(-414 kJ)
E)(+414 kJ)

Question 52

A concentration cell is constructed by using the same half-reaction for both the cathode and anode.What is the cell potential for a concentration cell that combines silver electrodes in contact with 0.25 M silver nitrate and 5.0 * 10^-4 M silver nitrate solutions?
(E °= +0.80 V for Ag/Ag⁺)

A)(+0.16 V)
B)(+0.64 V)
C)(+0.32 V)
D)(-0.16 V)
E)(+0.96 V)

Question 53

The change in free energy for a reaction, $\Delta$ G, depends on the stoichiometric coefficients used in writing the reaction, but cell potentials, E, do not depend on these coefficients.Which statement accounts for this difference?

A)These quantities $\Delta$ G and E) are not related, so this difference is not an issue.
B)The free-energy change is defined for general reactions, and the electromotive force is defined for electrochemical reactions, so this difference is not an issue.
C)The difference is not relevant because the units differ: kJ/mol for $\Delta$ G, and V for E.
D)The change in free energy depends on both the reaction and the amount of material reacting, while the cell potential depends only on the reaction.
E)The statement is false. $\Delta$ G does not depend on the stoichiometric coefficients.

Question 54

An electrochemical cell is constructed with a zinc metal anode in contact with a 0.052 M solution of zinc nitrate and a silver cathode in contact with a 0.0042 M solution of silver(I) nitrate.What is the value of Q to use in the Nernst equation for this cell?

A)2.9 * 10³
B)12
C)8.1* 10^-2
D)3.4 * 10^-4
E)1.00

Question 55

Which statement does NOT correctly describe a "dead" battery with a voltage of 0?

A)The free-energy change for the reaction now is 0.
B)All the reactants have been converted into products.
C)The products and reactants now are in equilibrium.
D)Q = K
E)cell potential= 0

Question 56

Which statement does NOT correctly describe a standard hydrogen electrode (SHE)?

A)The SHE is assigned a standard reduction potential of exactly 1 V.
B)2H ⁺ (aq) + 2e ^- $\rightarrow$ H₂ (g)
C)Pt | H₂(g, 1 atm) | H⁺(aq, 1 M) ||
D)|| H⁺(aq, 1 M) | H₂(g, 1 atm) | Pt
E)The SHE consists of a platinum electrode immersed in an acid solution and a stream of hydrogen gas.

Question 57

A concentration cell is constructed by using the same half-reaction for both the cathode and anode.What is the value of standard cell potential, E°, for a concentration cell that combines a silver anode in contact with 0.10 M silver nitrate and a silver cathode in contact with 3.0*10^-5 M silver nitrate?
(E° =0.80 V for Ag /Ag ⁺)

A)(-0.21 V)
B)0.00 V
C)0.80V
D)(-0.80 V)
E)(+0.21 V)

Question 58

An electrochemical cell has both a silver anode and a silver cathode.The solutions of silver nitrate in contact with the electrodes have different concentrations.Which statement(s) correctly describe(s) this cell?
I.The cell potential is 0.
II.The cell potential is negative.
III.The cell potential is positive.
IV.No electrons will flow through the external circuit.

A)I only
B)II only
C)III only
D)I and IV
E)II and IV

Question 59

Consider the voltaic cell based on the following reaction:
Zn(s) + Ni^{2 +}(aq) $\rightarrow$ Zn^{2 +}(aq) + Ni(s)
Two students are assigned to measure the standard cell potential at 25°C.Student 1 claims that both solutions of ions have to be at exactly 1.00 M concentration, but student 2 is sure that the measurement will be the same if the concentrations of the two solutions are equal, but not necessarily
1)00 M.What do you think?

A)Student 1 is right because, by definition, standard cell potentials must be measured at concentrations of 1.00 M.
B)Student 1 is right because she understands the Nernst equation and what it describes.
C)Student 2 is right because she understands the Nernst equation and what it describes.
D)Student 2 is right because cell potentials do not depend on the concentration.
E)Both are right because cell potentials do not depend on the concentration.

Question 60

An electrochemical cell at 298 K is made using a copper metal electrode immersed in a 0.30 M copper sulfate solution in one compartment (C1) and a copper metal electrode immersed in a 1.5 M copper sulfate solution in the other compartment (C2).Cu² sup>+(aq) + 2e ^- $\rightarrow$ Cu(s), E° = +0.34 V.Which statement regarding this electrochemical cell is FALSE?

A)The reaction continues until the copper ion concentrations in the two cells are equal.
B)The initial cell potential = 0.02 V.
C)The cell potential gradually decreases to 0.0 V.
D)The standard cell potential is +0.34 V.
E)Reduction occurs in compartment C2.

Question 61

Bubbles will form on wires attached to a 9 V battery placed in water.What is happening here?

A)The wires are being oxidized.
B)The water is being reduced on the wire attached to the( -) battery electrode and oxidized on the wire attached to the (+) battery electrode.
C)The water is being oxidized on the wire attached to the (-) battery electrode and reduced on the wire attached to the (+) battery electrode.
D)Air is being forced out of the water by the electric current.
E)One wire is being oxidized; the other wire is being reduced.

Question 62

The unit of electrical power, watt (W), is defined as

A)1 C.
B)1 V.
C)1 J.
D)1 C V.
E)1 J/s.

Question 63

The average electrical current delivered if 1.00 g of copper were oxidized to copper(II) in 60.0 s is

A)12.7 A.
B)25.3 A.
C)50.6 A.
D)3.15* 10^-2 A.
E)1.57 * 10^-2 A.

Question 64

The energy supplied by a battery can be determined by

A)multiplying amperes supplied by seconds.
B)dividing amperes supplied by seconds.
C)multiplying coulombs supplied by volts.
D)multiplying coulombs supplied by seconds.
E)dividing coulombs supplied by seconds.

Question 65

A concentration cell with a cell potential of +0.4759 V at 298 K is made using silver electrodes and aqueous silver ion solutions at 298 K.In one compartment, the Ag⁺ concentration is 1.000 M.In the other compartment, the Ag⁺ concentration is due to the dissolution of slightly soluble AgI.Calculate the value of K_sp for AgI.

A)8.362 *10^-17
B)7.935 *10^-4
C)0.8827
D)1.829 *10^-8
E)More information is needed.

Question 66

The electrodes on batteries are labeled +and -.The _____is labeled _____, and _____occurs there.

A)anode; positive; oxidation
B)anode; negative; oxidation
C)cathode; positive; oxidation
D)cathode; negative; reduction
E)anode; positive; reduction

Question 67

Electrochemical cell potentials can be used to determine equilibrium constants that would be otherwise difficult to determine because concentrations are small.Calculate the value of K_sp for CdS from the following data.
CdS(s) + 2e F^- $\rightarrow$ Cd(s) +S^{2 -}(aq) $\quad$$\quad$ E ° = -1.21 V
Cd^{2 +}(aq) +2e^- $\rightarrow$ Cd(s) $\quad$$\quad$$\quad$$\quad$$\quad$ E ° =-0.40 V

A)4.06*10^-55
B)4.32 * 10^-28
C)2.08 * 10^-14
D)2.31 * 10²⁷
E)2.47 * 10⁵⁴

Question 68

A pH meter uses an electrode arrangement that provides a voltage that depends on [H⁺], in accord with the Nernst equation.The following plot illustrates this dependence.What effect would changing temperature have on the measurement and this plot?

A)A change of temperature would have no effect.
B)An increase in temperature would increase the slope.
C)An increase in temperature would decrease the slope.
D)An increase in temperature would increase the y intercept.
E)An increase in temperature would decrease the y intercept.

Question 69

A concentration cell with a cell potential of +0.4759 V at 298 K is made using silver electrodes and aqueous silver ion solutions at 298 K.In one compartment, the Ag⁺ concentration is 1.000 M.In the other compartment, the Ag⁺ concentration is due to the dissolution of slightly soluble AgI.Calculate the concentration of the Ag⁺ in the saturated AgI solution.

A)8.36 *10^-17 M
B)0.0282 M
C)0.940 M
D)9.14 * 10^-9 M
E)More information is needed.

Question 70

The standard cell potential for the nickel-cadmium battery is 1.35 V, and the cell reaction can be written as 2 NiO(OH)(s) +2 H₂ O(l) + Cd(s) $\rightarrow$ 2 Ni(OH)2 (s) + Cd(OH)2 (s)
Which statement below is true based on the Nernst equation? Note: Q = reaction quotient, and
K = equilibrium constant for the cell reaction.

A)As the battery is used, the cell voltage approaches zero because Q approaches K in value.
B)When the battery no longer works, the cell voltage is zero because Q = K.
C)As the battery is used, the cell voltage does not change because Q equals 1.
D)When the battery is fully charged, Q K.
E)When the battery is fully charged, Q K.

Question 71

The Energizer Bunny in the television commercial "keeps going and going." What property of the battery voltaic cell) is being featured in this commercial?

A)the quantities of oxidizing agent and reducing agent in the battery
B)the high voltage of the battery
C)the low internal resistance of the battery
D)the excellent conductivity of the battery's casing
E)the ability of the battery to function over a wide temperature range

Question 72

The electrodes on batteries are labeled + and -.The______ is labeled _____, and ______occurs there.

A)anode; positive; oxidation
B)anode; negative; reduction
C)cathode; positive; reduction
D)cathode; negative; reduction
E)cathode; positive; oxidation

Question 73

Which one of the following is NOT an advantage of lithium batteries?

A)the extremely negative standard reduction potential of lithium
B)the small molar mass of lithium
C)the high mobility of lithium in solids
D)the small cell potentials produced by these batteries
E)a high battery capacity

Question 74

The spontaneous redox reaction in a voltaic cell has

A)E^o _cell 0, $\Delta$ G° 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 0, and K 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 1
B)E^o_cell 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 0, $\Delta$ G° 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 0, and K 1
C)E^o _cell 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 0, $\Delta$ G° 11eed928_5622_4673_a0ba_f5daa2fc20ab_TB6562_11 0, and K 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 1
D)E^o _cell 0, (\Delta\) G° 11eed927_f2e6_11e2_a0ba_15d493ae4d84_TB6562_11 0, and K 11eed927_f2e6_11e2_a0ba_15d493ae4d84_TB6562_11 1
E)E^o_cell 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 0, $\Delta$ G° = 0, and K 11eed928_8239_0c84_a0ba_7181550d35e5_TB6562_11 1

Question 75

The unit of current, the ampere (A), is defined as

A)1 C.
B)1 C/s.
C)1 mole of electrons.
D)1 mole of electrons per second.
E)96,500 C/s.

Question 76

When a voltaic cell reaches equilibrium,

A)E^o _cell = 0.
B)E_cell = 0.
C)E_cell = K.
D)E^o _cell= K. cell cell
E)E_cell = Q.

Question 77

A NiMH battery uses _____as the reducing agent.

A)nickel
B)a metal hydride
C)hydroxide
D)hydronium ion
E)nickel oxide

Question 78

Suppose the redox reaction in a certain zinc-carbon battery is Zn +2 MnO₂ + 2 NH₄ Cl $\rightarrow$ MN₂ O₃ +Zn(NH₃ )2 CL₂ + H₂ O.The battery is rated at 4.5 W _• hr at 1.5 V.How many grams of zinc must be oxidized to deliver this much charge?

A)11 g Zn
B)1.8 g Zn
C)3.7 g Zn
D)8.2 g Zn
E)5.5 g Zn

Question 79

The charge supplied by a battery can be determined by

A)multiplying amperes by seconds.
B)dividing amperes by seconds.
C)multiplying coulombs by volts.
D)multiplying coulombs by seconds.
E)dividing coulombs by seconds.

Question 80

A NiMH battery uses _____as the oxidizing agent.

A)Ni
B)MH
C)hydroxide
D)hydronium ion
E)NiOOH)