Deck 17: Electrochemistry-The Quest for Clean Energy

Question 1

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.

Answer 1

A good reducing agent is a metal in a high oxidation state,such as Mn⁷⁺.

Question 2

You are to determine the amount of vitamin C (ascorbic acid)in orange juice by redox titration.The ascorbate,C₆H₇O₆^-,in the juice reacts with triiodide,I₃^- to form dehydroascorbate,C₆H₅O₆^-,and iodide,I^-.How many electrons are transferred in the reaction? The reaction describing the titration is given below. C₆H₇O₆^-(aq)+ I₃^-(aq) $\to$ C₆H₅O₆^-(aq)+ 2 H⁺(aq)+ 3 I^-(aq)

A)1
B)2
C)4
D)0
E)It is impossible to tell.

Answer 2

2

Question 3

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 3

on the left

Question 4

Consider the reaction,Au(s)+ Cl₂(g) $\to$ AuCl₄^-(aq). Which statement,A-D,is NOT correct? If more than one is NOT correct,respond E.

A)Au loses three electrons in the oxidation half-reaction.
B)Each chlorine atom gains two electrons in the reduction half-reaction.
C)Au is the oxidizing agent.
D)There is no way to balance this equation as written.
E)More than one statement is NOT correct.

Question 5

The following reaction occurs in acidic solution.Identify the correct half-reaction that applies to the oxidizing agent.(Note: The equation is not balanced.) Cr₂O₇^2-(aq)+ C₂H₅OH(aq) $\to$ C₂H₄O(aq)+ Cr³⁺(aq)

A)C₂H₅OH $\to$ C₂H₄O + 2 H⁺ + 2 e^-
B)Cr₂O₇^2- + 3 e^- $\to$ Cr³⁺ + 7 H₂O
C)C₂H₅OH + 2 e^-+ 2 H⁺ $\to$ C₂H₄O + H₂O
D)14 H⁺ + Cr₂O₇^2- $\to$ 2 Cr³⁺ + 7 H₂O + 8 e^-
E)14 H⁺ + Cr₂O₇^2- + 6 e^- $\to$ 2 Cr³⁺ + 7 H₂O

Question 6

The following reaction occurs in basic solution.Identify the reducing agent.(Note: The equation is not balanced.) Zn(s)+ NO₃^-(aq) $\to$ Zn(OH)₄^2-(aq)+ NH₃(aq)

A)Zn(s)
B)NO₃^-(aq)
C)OH^-(aq)
D)H₂O( )
E)NH₃(aq)

Question 7

Reduction is the ________

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

Question 8

The following reaction occurs in basic solution.Identify the correct oxidation half-reaction.(Note: The equation is not balanced.) Zn(s)+ NO₃^-(aq) $\to$ Zn(OH)₄^2-(aq)+ NH₃(aq)

A)Zn $\to$ Zn(OH)₄^2- + 2 e^-
B)Zn + 2 H₂O $\to$ Zn(OH)₄^2- + 2 e^-
C)Zn + 4 OH^- $\to$ Zn(OH)₄^2- + 2 e^-
D)NO₃^- + 8 e^- $\to$ NH₃
E)NO₃^- + 6 H₂O + 8 e^- $\to$ NH₃ + 9 OH^-

Question 9

The following reaction occurs in basic solution.Identify the correct reduction half-reaction.(Note: The equation is not balanced.) Zn(s)+ NO₃^-(aq) $\to$ Zn(OH)₄^2-(aq)+ NH₃(aq)

A)Zn $\to$ Zn(OH)₄^2- + 2 e^-
B)Zn + 2 H₂O $\to$ Zn(OH)₄^2- + 2 e^-
C)Zn + 4 OH^- $\to$ Zn(OH)₄^2- + 2 e^-
D)NO₃^- + 8 e^- $\to$ NH₃
E)NO₃^- + 6 H₂O + 8 e^- $\to$ NH₃ + 9 OH^-

Question 10

The following reaction occurs in basic solution.Identify the oxidizing agent.(Note: The equation is not balanced.) Zn(s)+ NO₃^-(aq) $\to$ Zn(OH)₄^2-(aq)+ NH₃(aq)

A)H₂O( )
B)NO₃^-(aq)
C)OH^-(aq)
D)Zn(s)
E)NH₃(aq)

Question 11

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 12

What is the oxidation number of chromium in the ionic compound ammonium dichromate,(NH₄)₂Cr₂O₇?

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

Question 13

Proteins containing a certain functional group (identified as RSH)can be titrated with 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) $\to$ 3 I^-(aq)+ RSSR(aq)+ 2 H⁺(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 14

Oxidation is the ________

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

Question 15

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 16

Consider the reaction,Sn + Au³⁺ $\to$ Sn²⁺ + Au.Which of the following is NOT correct? If more than one is NOT correct,respond E.

A)The oxidation half-reaction is Sn $\to$ Sn²⁺ + 2 e^-.
B)The reduction half-reaction is Au³⁺ + 3 e^- $\to$ Au.
C)Au³⁺ is the oxidizing agent.
D)The equation is balanced as written.
E)More than one statement is NOT correct.

Question 17

In the smelting of iron from iron oxide according to the equation Fe₂O₃(s)+ 3 CO(g) $\to$ 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 18

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.

Question 19

When hydrogen reacts with a metal to form a hydride (e.g.,CaH₂),what are the oxidation numbers of the calcium (in this case)and hydrogen,respectively,in the product?

A)"-2 and +1"
B)"+1 and -2"
C)"+2 and -1
D)"0 and 0"
E)"+2 and -2"

Question 20

The following reaction occurs in acidic solution.Identify the correct half-reaction that applies to the reducing agent.(Note: The equation is not balanced.) Cr₂O₇^2-(aq)+ C₂H₅OH(aq) $\to$ C₂H₄O(aq)+ Cr³⁺(aq)

A)C₂H₅OH $\to$ C₂H₄O + 2 H⁺ + 2 e^-
B)Cr₂O₇^2- + 3 e^- $\to$ Cr³⁺ + 7 H₂O
C)C₂H₅OH + 2 e^-+ 2 H⁺ $\to$ C₂H₄O + H₂O
D)14 H⁺ + Cr₂O₇^2- $\to$ 2 Cr³⁺ + 7 H₂O + 8 e^-
E)14 H⁺ + Cr₂O₇^2- + 6 e^- $\to$ 2 Cr³⁺ + 7 H₂O

Question 21

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver (I)ions.Solutions of 1.00 M silver nitrate and zinc nitrate also were used.The anode is on the left; the cathode,on the right.Where does oxidation occur?

A)a
B)b
C)c
D)d
E)e

Question 22

Balance the chemical equation for the following redox reaction under basic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.What is the coefficient of ClO^-? ClO^-(aq)+ Pb(OH)₄^2-(aq) $\to$ Cl^-(aq)+ PbO₂(s)

A)1
B)2
C)3
D)5
E)10

Question 23

Based on the cell diagram,Fe(s)| Fe²⁺(aq)|| O₂(g)| H⁺(aq),H₂O( )| Pt(s),which of the following statements is NOT correct?

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 24

Balance the chemical equation for the following redox reaction under basic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.How many moles of electrons are transferred in the balanced reaction? ClO₃^-(aq)+ N₂H₄(g) $\to$ Cl^-(aq)+ NO(g)

A)6
B)8
C)16
D)24
E)48

Question 25

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver (I)ions.Solutions of 1.00 M silver nitrate and zinc nitrate also were used.The anode is on the left; the cathode,on the right.Where does reduction occur?

A)a
B)b
C)c
D)d
E)e

Question 26

Which statement about a cathode in a voltaic cell is NOT correct?

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 27

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 28

Balance the chemical equation for the following redox reaction under acidic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.What is the coefficient of C₂H₅OH? Cr₂O₇^2-(aq)+ C₂H₅OH(aq) $\to$ Cr³⁺(aq)+ CO₂(g)

A)1
B)2
C)3
D)4
E)5

Question 29

Which statement regarding voltaic cells is NOT correct?

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 30

Balance the chemical equation for the following redox reaction under acidic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.What is the coefficient of Cl^-? Cl₂(g)+ S₂O₃^2-(aq) $\to$ Cl^-(aq)+ SO₄^2-(aq)

A)2
B)4
C)5
D)8
E)10

Question 31

A voltaic cell is constructed based on the reaction of Zn(s)with Pb²⁺(aq)producing Zn²⁺(aq)and Pb(s).Identify the correct cell diagram.

A)Zn²⁺(aq)| Pb²⁺(aq)|| Zn(s)| Pb(s)
B)Zn(s)| Zn²⁺(aq)|| Pb²⁺(aq)| Pb(s)
C)Zn(s)| Pb²⁺(aq)|| Zn²⁺(aq)| Pb(s)
D)Pb²⁺(aq)| Pb(s)|| Zn(s)| Zn²⁺(aq)
E)Pb(s)| Pb²⁺(aq)|| Zn²⁺(aq)| Zn(s)

Question 32

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver (I)ions.Solutions of 1.00 M silver nitrate and zinc nitrate also were used.The anode is on the left; the cathode,on the right.Locate the zinc nitrate solution on the diagram.

A)a
B)b
C)c
D)d
E)e

Question 33

Balance the chemical equation for the following redox reaction under acidic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.How many moles of electrons are transferred in the balanced reaction? Te(s)+ ClO₃^-(aq) $\to$ H₆TeO₆(aq)+ Cl₂(g)

A)5
B)6
C)10
D)15
E)30

Question 34

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver (I)ions.Solutions of 1.00 M silver nitrate and zinc nitrate also were used.The anode is on the left; the cathode,on the right.Locate the silver electrode on the diagram.

A)a
B)b
C)c
D)d
E)e

Question 35

Which of the following statements regarding reduction potentials is NOT correct?

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)The reduction potential of a substance depends on conditions such as concentration and pH.

Question 36

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

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

Question 37

Balance the chemical equation for the following redox reaction under basic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.On which side does OH^- appear,and what is its coefficient? ClO₃^-(aq)+ N₂H₄(g) $\to$ Cl^-(aq)+ NO(g)

A)right,2
B)left,4
C)left,1
D)right,3
E)OH^- is not required to balance the equation

Question 38

Which statement about a voltaic cell is NOT correct?

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 39

Balance the chemical equation for the following redox reaction under acidic aqueous conditions with the smallest whole-number coefficients possible using the half-reaction method.On which side does H₂O(l)appear,and what is its coefficient? Te(s)+ ClO₃^-(aq) $\to$ H₆TeO₆(aq)+ Cl₂(g)

A)left,6
B)right,6
C)left,12
D)right,12
E)left,30

Question 40

A voltaic cell is constructed based on the oxidation of zinc metal and the reduction of silver (I)ions.Solutions of 1.00 M silver nitrate and zinc nitrate also were used.The anode is on the left; the cathode,on the right.Locate the silver nitrate solution on the diagram.

A)a
B)b
C)c
D)d
E)e

Question 41

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 Mn(VII).
E)An example of a good oxidizing agent is an alkali metal,such as Na.

Question 42

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 $\to$ Al³⁺ + 3 e^-
B)Ag⁺ + e^- $\to$ Ag
C)2 HCO₃^-+S^2- $\to$ H₂S + 2 CO₃^2-
D)3 Ag₂S + 2 Al +3 H₂O $\to$ 6 Ag + Al₂O₃ +3 H₂S
E)2 HCO₃^-+Ag₂S $\to$ H₂S + 2 CO₃^2- + 2 Ag

Question 43

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 44

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)"+3.14 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 45

Using the following data,determine the standard cell potential for the electrochemical cell constructed using the following reaction: Zn(s)+ Pb²⁺(aq) $\to$ Zn²⁺(aq)+ Pb(s). Half-reaction Standard reduction potential
Zn²⁺(aq)+ 2 e^- $\to$ Zn(s) -0.763
Pb²⁺(aq)+ 2 e^- $\to$ Pb(s) -0.126

A)"+0.637 V
B)"-0.637 V"
C)"+1.274 V"
D)"-0.889 V"
E)"+0.889 V"

Question 46

Based on the information in the table of standard reduction potentials below,calculate for Mg²⁺ + 2 I ^- $\to$ Mg + I₂.

A)"+1.84 V"
B)"+3.44 V"
C)"-3.44 V"
D)"-2.91 V"
E)"+2.91 V"

Question 47

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.

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

Question 48

Using the following standard reduction potentials,calculate the cell potential for the voltaic cell that would have the largest .

A)2.70 V
B)2.43 V
C)2.17 V
D)2.09 V
E)1.83 V

Question 49

Use the table of standard reduction potentials below to identify which of the following statements is NOT correct.

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 50

Copper is oxidized by nitric acid.If this property were utilized in an electrochemical cell,what would the standard cell potential be? The relevant reduction reactions and standard reduction potentials are given below.

A)"-0.62 V"
B)"+0.62 V"
C)"-1.30 V"
D)"+1.30 V"
E)"+0.68 V"

Question 51

Using the following data,determine for the electrochemical cell constructed using the reaction of nitrous oxide and oxalic acid under acidic conditions.Unbalanced: N₂O(g)+ H₂C₂O₄(s) $\to$ 2 CO₂(g)+ N₂(g)+ H₂O( )
Half-reaction Standard reduction potential
2 CO₂(g)+ 2 H⁺(aq)+ 2 e^- $\to$ H₂C₂O₄(s)-0.49
N₂O(g)+ 2 H⁺(aq)+ 2 e^- $\to$ N₂(g)+ H₂O( )+1.78

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

Question 52

Based on the information in the table of standard reduction potentials below,calculate for Al(s)| Al³⁺(aq)|| Br₂(aq),Br ^-(aq).

A)"+0.12 V"
B)"+2.73 V"
C)"-2.73 V"
D)"-0.59 V"
E)"+0.59 V"

Question 53

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 following statements is correct?

A)Aluminum ions react with S^2-,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 silver(I)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 54

Using the following standard reduction potentials,calculate the for the reaction of tin with chromium(III)hydroxide producing tin(IV)oxide and chromium under basic conditions.

A)"+3.07 V"
B)"-2.43 V"
C)"+2.43 V"
D)"+0.53 V"
E)"-0.53V"

Question 55

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

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 56

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

A)Pb⁴⁺
B)Pb²⁺
C)K⁺
D)K
E)Al

Question 57

Using the following data,determine the standard cell potential for the electrochemical cell constructed based on the following unbalanced reaction expression: Al(s)+ Cr³⁺(aq) $\to$ Al³⁺(g)+ Cr²⁺(aq).
Half-reaction Standard reduction potential
Al³⁺(aq)+ 3 e^- $\to$ Al(s)-1.66
Cr³⁺(aq)+ e^- $\to$ Cr²⁺(aq)-0.41

A)"-1.25 V
B)"+1.25 V"
C)"+2.07 V"
D)"-0.43 V"
E)"+0.43 V"

Question 58

What is the standard cell potential for a voltaic cell using the Pb²⁺/Pb and Mg²⁺/Mg half-reactions? Which metal is the cathode?

A)"-2.25 V,Pb is the cathode"
B)"+2.25 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 59

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

A)Pb⁴⁺
B)Pb²⁺
C)K⁺
D)K
E)Al

Question 60

Using the following data,determine for the electrochemical cell constructed using the reaction of zinc and chromate ions under basic conditions.Unbalanced: Zn(s)+ 2 CrO₄^2-(aq) $\to$ Zn(OH)₂(s)+ Cr(OH)₃(s)
Half-reaction Standard reduction potential
Zn(OH)₂(s)+ 2 e^- $\to$ Zn(s)+ 2 OH^-(aq) -1.25
CrO₄^2-(aq)+ 4 H₂O( )+ 3 e^- $\to$ Cr(OH)₃(s)+ 5 OH^-(aq)-0.13

A)"-3.49 V"
B)"+3.49 V"
C)"+1.12 V"
D)"-1.12 V"
E)"+1.38 V"

Question 61

Calculate for an electrochemical cell reaction that occurs under acidic 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.
Cr₂O₇^2- + 14 H⁺ + 6 e^- $\to$ 2 Cr³⁺ + 7 H₂O $\quad$ $\quad$ +1.33 V
CH₃COOH + 4 H⁺ + 4 e^- $\to$ C₂H₅OH + H₂O $\quad$ +0.058 V

A)"-1610 kJ"
B)"+1610 kJ"
C)"-1470 kJ"
D)"+2880 kJ"
E)"-2880 kJ"

Question 62

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 $\times$ 10² kJ
B)4.34 $\times$ 10² kJ
C)8.69 $\times$ 10² kJ
D)2.90 $\times$ 10² kJ
E)72.4 kJ

Question 63

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 the temperature and reactant concentrations.
E)cell potentials from standard oxidation potentials.

Question 64

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)"-1.200 kJ"
E)"+602 kJ"

Question 65

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)2 H⁺(aq)+ 2 e^- $\to$ 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 66

Based on the information in the table of standard reduction potentials below,calculate $\Delta$ G $\gamma$ for the redox reaction of bromine with potassium.

A)"+359 kJ"
B)"-359 kJ"
C)"-1340 kJ"
D)"+1340 kJ"
E)"-771 kJ"

Question 67

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 cathode and silver anode

Question 68

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 $\times$ 10² kJ
B)4.34 $\times$ 10² kJ
C)8.69 $\times$ 10² kJ
D)2.90 $\times$ 10² kJ
E)72.4 kJ

Question 69

Calculate 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 + 2 e^- $\to$ Cd + 2 OH^- $\quad$ $\quad$ $\quad$ -0.824 V
NiO(OH)+ H₂O + e^- $\to$ 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 70

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 $\times$ 10² kJ"
B)"+1.45 $\times$ 10² kJ"
C)"+5.79 $\times$ 10² kJ"
D)"-8.69 $\times$ 10² kJ"
E)"-2.90 $\times$ 10² kJ"

Question 71

The spontaneous redox reaction in a voltaic cell has ________

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

Question 72

Based on the information in the table of standard reduction potentials below,calculate $\Delta$ G $\gamma$ for 2Pb²⁺ $\to$ Pb + Pb⁴⁺.

A)"+371 kJ"
B)"-371 kJ"
C)"-323 kJ"
D)"+323 kJ"
E)"-186 kJ"

Question 73

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 74

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 $\times$ 10³
B)12
C)8.1 $\times$ 10^-2
D)3.4 $\times$ 10^-4
E)1.00

Question 75

The magnitude of the charge on a mole of electrons is ________

A)"1 C."
B)"9.65 C."
C)"9.65 $\times$ 10⁴ C."
D)"6.02 $\times$ 10²³ C."
E)"9650 C."

Question 76

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 77

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 78

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 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 79

Which of the following statements regarding chemical energy and electrical work is NOT correct?

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 80

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.