Question 1

A voltaic cell consists of a Mn/Mn2+ electrode (E° = −1.18 V)  and a Fe/Fe2+ electrode (E° = −0.44 V) . Calculate [Fe2+] if [Mn2+] = 0.050 M and Ecell = 0.78 V at 25°C.

Accepted Answer

A)  0.040 M
B)  0.24 M
C)  1.1 M
D)  1.8 M
E)  None of these choices are correct.F) A) and B)
G) All of the above

Question 2

When metal A is placed in a solution of metal ions B2+, a reaction occurs between A and B2+, and metal ions A2+ appear in the solution. When metal B is placed in acid solution, gas bubbles form on its surface. When metal A is placed in a solution of metal ions C2+, no reaction occurs. Which of the following reactions would not occur spontaneously?

Accepted Answer

A)  C( s) + 2H +( aq) → H 2( g) + C 2+( aq) 
B)  C( s) + A 2+( aq) → A( s) + C 2+( aq) 
C)  B( s) + C 2+( aq) → C( s) + B 2+( aq) 
D)  A( s) + 2H +( aq) → H 2( g) + A 2+( aq) 
E)  B( s) + 2H +( aq) → H 2( g) + B 2+( aq) F) A) and C)
G) A) and B)

Question 3

A voltaic cell consists of a Hg/Hg22+ electrode (E° = 0.85 V)  and a Sn/Sn2+ electrode (E° = −0.14 V) . Calculate [Sn2+] if [Hg22+] = 0.24 M and Ecell = 1.04 V at 25°C.

Accepted Answer

A)  0.0001 M
B)  0.0007 M
C)  0.005 M
D)  0.03 M
E)  0.05 MF) C) and E)
G) A) and B)

Question 4

If the equilibrium constant Kc is greater than 1 for a given reaction, predict the signs of ΔG° and E° at the same temperature.

Accepted Answer

A)  Δ G° > 0; E° > 0
B)  ΔG° 
C)  Δ G° > 0; E° 
D)  Δ G°  0
E)  Cannot predict - it depends on the temperature.F) All of the above
G) None of the above

Question 5

If the electrodes of a voltaic cell are connected with an external wire, electrons will flow in this wire from the cathode to the anode.

Accepted Answer

A) True 
 B)False

Question 6

Examine the following half-reactions and select the strongest reducing agent among the species listed. HgO(s)  + H2O(l)  + 2e− ⇄ Hg(l)  + 2OH−(aq)  E° = 0.0977 V
Zn(OH) 2(s)  + 2e− ⇄ Zn(s)  + 2OH−(aq)  E° = −1.25 V
Ag2O(s)  + H2O(l)  + 2e− ⇄ Ag(s)  + 2OH−(aq)  E° = 0.342 V
B(OH) 3(aq)  + 7H+(aq)  + 8e− ⇄ BH4−(aq)  + 3H2O(l)  E° = −0.481 V

Accepted Answer

A)  Hg( l) 
B)  Zn( s) 
C)  Ag( s) 
D)  BH 4 −( aq) 
E)  Zn(OH) 2( s) F) None of the above
G) A) and D)

Question 7

Calculate the potential of a voltaic cell (E°cell)  if it is required to do 5.43 × 10−3 kJ of work when a charge of 2.50 C is transferred.

Accepted Answer

A)  2.17 × 10 3 V
B)  2.17 × 10 −3 V
C)  2.17 V
D)  13.6 V
E)  1.36 × 10 −2 VF) A) and D)
G) B) and D)

Question 8

Consider the following balanced redox reaction 3CuO(s)  + 2NH3(aq)  → N2(g)  + 3H2O(l)  + 3Cu(s) 
Which of the following statements is true?

Accepted Answer

A)  CuO( s) is the oxidizing agent and copper is reduced.
B)  CuO( s) is the oxidizing agent and copper is oxidized.
C)  CuO( s) is the reducing agent and copper is oxidized.
D)  CuO( s) is the reducing agent and copper is reduced.
E)  CuO( s) is the oxidizing agent and N 2( g) is the reducing agent.F) A) and E)
G) None of the above

Question 9

Which of the following conditions is most likely to apply to a fully-charged secondary cell?

Accepted Answer

A)  E cell = E° cell
B)  E° cell = 0
C)  Q = 1
D)  Q 
E)  Q = KF) A) and B)
G) C) and D)

Question 10

Consider the following redox equation Mn(OH) 2(s)  + MnO4(aq)  → MnO42−(aq)  (basic solution) 
When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH−(aq)  and on which side of the equation is OH−(aq)  present?

Accepted Answer

A)  4, reactant side
B)  4, product side
C)  6, reactant side
D)  6, product side
E)  None of these choices are correct.F) A) and D)
G) B) and D)

Question 11

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be Zn(s)  + ReO4(aq)  → Re(s)  + Zn2+(aq)  (acidic solution)

Accepted Answer

A)  2.
B)  7.
C)  8.
D)  16.
E)  None of these choices are correct.F) A) and D)
G) C) and D)

Question 12

Which one of the following pairs of substances could be used to construct a single redox electrode (i.e., they have an element in common, but in different oxidation states) ?

Accepted Answer

A)  HCl and Cl −
B)  H + and OH −
C)  H 2O and H +
D)  Fe 3+ and Fe 2O 3
E)  MnO 2 and Mn 2+F) A) and C)
G) A) and D)

Question 13

In the electrolysis of aqueous potassium nitrate using inert electrodes, which one of the following species is oxidized?

Accepted Answer

A)  Potassium ion
B)  Nitrate ion
C)  Water
D)  Oxygen
E)  Hydronium ionF) C) and E)
G) C) and D)

Question 14

Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. I2(s)  + 2e− ⇄ 2I− (aq)  E° = 0.53 V
Cr3+(aq)  + 3e− ⇄ Cr(s)  E° = −0.74 V
Overall reaction:
2Cr(s)  + 3I2(s)  → 2Cr3+(aq)  + (aq)  + 6I−(aq)

Accepted Answer

A)  E° cell = −1.27 V, spontaneous
B)  E° cell = −1.27 V, nonspontaneous
C)  E° cell = 1.27 V, spontaneous
D)  E° cell = 1.27 V, nonspontaneous
E)  E° cell = 1.54 V, spontaneousF) A) and B)
G) B) and D)

Question 15

Consider the reaction CuO(s)  + H2(g)  → Cu(s)  + H2O(l) 
In this reaction, which substances are the oxidant and reductant, respectively?

Accepted Answer

A)  CuO and H 2
B)  H 2 and CuO
C)  CuO and Cu
D)  H 2O and H 2
E)  None of these choices are correct.F) A) and E)
G) A) and D)

Question 16

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.61 V 2Cr(s)  + 3Pb2+(aq)  ⇄ 3Pb(s)  + 2Cr3+(aq)

Accepted Answer

A)  4.1 × 10 20
B)  8.2 × 10 30
C)  3.3 × 10 51
D)  7.4 × 10 61
E)  > 9.9 × 10 99F) A) and D)
G) A) and B)

Question 17

Examine the following half-reactions and select the strongest oxidizing agent among the species listed. Cr2+(aq)  + 2e− ⇄ Cr(s)  E° = -0.913 V
Fe2+(aq)  + 2e−⇄ Fe(s)  E° = -0.447 V
Sr2+(aq)  + 2e−⇄ Sr(s)  E° = -2.89 V
Co2+(aq)  + 2e−⇄ Co(s)  E° = -0.28 V

Accepted Answer

A)  Cr 2+( aq) 
B)  Fe( s) 
C)  Fe 2+( aq) 
D)  Sr 2+( aq) 
E)  Co 2+( aq) F) A) and B)
G) A) and C)

Question 18

A buried iron pipe can be protected against corrosion by connecting it to a rod of copper.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following elements could be prepared by electrolysis of the aqueous solution shown?

Accepted Answer

A)  Sodium from Na 3PO 4( aq) 
B)  Sulfur from K 2SO 4( aq) 
C)  Oxygen from H 2SO 4( aq) 
D)  Potassium from KCl( aq) 
E)  Nitrogen from AgNO 3( aq) F) A) and D)
G) D) and E)

Question 20

A voltaic cell consists of an Au/Au3+ electrode (E° = 1.50 V)  and a Cu/Cu2+ electrode (E° = 0.34 V) . Calculate [Au3+] if [Cu2+] = 1.20 M and Ecell = 1.13 V at 25°C.

Accepted Answer

A)  0.001 M
B)  0.002 M
C)  0.01 M
D)  0.02 M
E)  0.04 MF) A) and E)
G) B) and E)

Exam 21: Electrochemistry: Chemical Change and Electrical Work

Correct Answer
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A voltaic cell consists of a Hg/Hg₂²⁺ electrode (E° = 0.85 V) and a Sn/Sn²⁺ electrode (E° = −0.14 V) . Calculate [Sn²⁺] if [Hg₂²⁺] = 0.24 M and E_cell = 1.04 V at 25°C.

Correct Answer
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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be Zn(s) + ReO₄(aq) → Re(s) + Zn²⁺(aq) (acidic solution)

Correct Answer
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Correct Answer
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Consider the reaction CuO(s) + H₂(g) → Cu(s) + H₂O(l) In this reaction, which substances are the oxidant and reductant, respectively?

Correct Answer
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Calculate E°_cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. I₂(s) + 2e⁻ ⇄ 2I⁻ (aq) E° = 0.53 V Cr³⁺(aq) + 3e⁻ ⇄ Cr(s) E° = −0.74 V Overall reaction: 2Cr(s) + 3I₂(s) → 2Cr³⁺(aq) + (aq) + 6I⁻(aq)

Correct Answer
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In the electrolysis of aqueous potassium nitrate using inert electrodes, which one of the following species is oxidized?

Correct Answer
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Which of the following elements could be prepared by electrolysis of the aqueous solution shown?

Correct Answer
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If the equilibrium constant K_c is greater than 1 for a given reaction, predict the signs of ΔG° and E° at the same temperature.

Correct Answer
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A voltaic cell consists of a Mn/Mn²⁺ electrode (E° = −1.18 V) and a Fe/Fe²⁺ electrode (E° = −0.44 V) . Calculate [Fe²⁺] if [Mn²⁺] = 0.050 M and E_cell = 0.78 V at 25°C.

Correct Answer
verified

A buried iron pipe can be protected against corrosion by connecting it to a rod of copper.

Correct Answer
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If the electrodes of a voltaic cell are connected with an external wire, electrons will flow in this wire from the cathode to the anode.

Correct Answer
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What is the value of the equilibrium constant for the cell reaction below at 25°C? E°_cell = 0.61 V 2Cr(s) + 3Pb²⁺(aq) ⇄ 3Pb(s) + 2Cr³⁺(aq)

Correct Answer
verified

Calculate the potential of a voltaic cell (E°_cell) if it is required to do 5.43 × 10⁻³ kJ of work when a charge of 2.50 C is transferred.

Correct Answer
verified

Which of the following conditions is most likely to apply to a fully-charged secondary cell?

Correct Answer
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A voltaic cell consists of an Au/Au³⁺ electrode (E° = 1.50 V) and a Cu/Cu²⁺ electrode (E° = 0.34 V) . Calculate [Au³⁺] if [Cu²⁺] = 1.20 M and E_cell = 1.13 V at 25°C.

Correct Answer
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Consider the following balanced redox reaction 3CuO(s) + 2NH₃(aq) → N₂(g) + 3H₂O(l) + 3Cu(s) Which of the following statements is true?

Correct Answer
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Examine the following half-reactions and select the strongest oxidizing agent among the species listed. Cr²⁺(aq) + 2e⁻⇄ Cr(s) E° = -0.913 V Fe²⁺(aq) + 2e⁻⇄ Fe(s) E° = -0.447 V Sr²⁺(aq) + 2e⁻⇄ Sr(s) E° = -2.89 V Co²⁺(aq) + 2e⁻⇄ Co(s) E° = -0.28 V

Correct Answer
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Which one of the following pairs of substances could be used to construct a single redox electrode (i.e., they have an element in common, but in different oxidation states) ?

Correct Answer
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Consider the following redox equation Mn(OH) ₂(s) + MnO₄(aq) → MnO₄²⁻(aq) (basic solution) When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH⁻(aq) and on which side of the equation is OH⁻(aq) present?

Correct Answer
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Exam 21: Electrochemistry: Chemical Change and Electrical Work

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A voltaic cell consists of a Hg/Hg22+ electrode (E° = 0.85 V) and a Sn/Sn2+ electrode (E° = −0.14 V) . Calculate [Sn2+] if [Hg22+] = 0.24 M and Ecell = 1.04 V at 25°C.

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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be Zn(s) + ReO4(aq) → Re(s) + Zn2+(aq) (acidic solution)

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Correct AnswerverifiedShow Answer

Consider the reaction CuO(s) + H2(g) → Cu(s) + H2O(l) In this reaction, which substances are the oxidant and reductant, respectively?

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Calculate E°cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. I2(s) + 2e− ⇄ 2I− (aq) E° = 0.53 V Cr3+(aq) + 3e− ⇄ Cr(s) E° = −0.74 V Overall reaction: 2Cr(s) + 3I2(s) → 2Cr3+(aq) + (aq) + 6I−(aq)

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In the electrolysis of aqueous potassium nitrate using inert electrodes, which one of the following species is oxidized?

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Which of the following elements could be prepared by electrolysis of the aqueous solution shown?

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If the equilibrium constant Kc is greater than 1 for a given reaction, predict the signs of ΔG° and E° at the same temperature.

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A voltaic cell consists of a Mn/Mn2+ electrode (E° = −1.18 V) and a Fe/Fe2+ electrode (E° = −0.44 V) . Calculate [Fe2+] if [Mn2+] = 0.050 M and Ecell = 0.78 V at 25°C.

Correct AnswerverifiedShow Answer

A buried iron pipe can be protected against corrosion by connecting it to a rod of copper.

Correct AnswerverifiedShow Answer

If the electrodes of a voltaic cell are connected with an external wire, electrons will flow in this wire from the cathode to the anode.

Correct AnswerverifiedShow Answer

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°cell = 0.61 V 2Cr(s) + 3Pb2+(aq) ⇄ 3Pb(s) + 2Cr3+(aq)

Correct AnswerverifiedShow Answer

Calculate the potential of a voltaic cell (E°cell) if it is required to do 5.43 × 10−3 kJ of work when a charge of 2.50 C is transferred.

Correct AnswerverifiedShow Answer

Which of the following conditions is most likely to apply to a fully-charged secondary cell?

Correct AnswerverifiedShow Answer

A voltaic cell consists of an Au/Au3+ electrode (E° = 1.50 V) and a Cu/Cu2+ electrode (E° = 0.34 V) . Calculate [Au3+] if [Cu2+] = 1.20 M and Ecell = 1.13 V at 25°C.

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Consider the following balanced redox reaction 3CuO(s) + 2NH3(aq) → N2(g) + 3H2O(l) + 3Cu(s) Which of the following statements is true?

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Examine the following half-reactions and select the strongest oxidizing agent among the species listed. Cr2+(aq) + 2e− ⇄ Cr(s) E° = -0.913 V Fe2+(aq) + 2e−⇄ Fe(s) E° = -0.447 V Sr2+(aq) + 2e−⇄ Sr(s) E° = -2.89 V Co2+(aq) + 2e−⇄ Co(s) E° = -0.28 V

Correct AnswerverifiedShow Answer

Which one of the following pairs of substances could be used to construct a single redox electrode (i.e., they have an element in common, but in different oxidation states) ?

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Consider the following redox equation Mn(OH) 2(s) + MnO4(aq) → MnO42−(aq) (basic solution) When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH−(aq) and on which side of the equation is OH−(aq) present?

Correct AnswerverifiedShow Answer

Correct Answer
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A voltaic cell consists of a Hg/Hg₂²⁺ electrode (E° = 0.85 V) and a Sn/Sn²⁺ electrode (E° = −0.14 V) . Calculate [Sn²⁺] if [Hg₂²⁺] = 0.24 M and E_cell = 1.04 V at 25°C.

Correct Answer
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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for zinc will be Zn(s) + ReO₄(aq) → Re(s) + Zn²⁺(aq) (acidic solution)

Correct Answer
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Correct Answer
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Consider the reaction CuO(s) + H₂(g) → Cu(s) + H₂O(l) In this reaction, which substances are the oxidant and reductant, respectively?

Correct Answer
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Calculate E°_cell and indicate whether the overall reaction shown is spontaneous or nonspontaneous. I₂(s) + 2e⁻ ⇄ 2I⁻ (aq) E° = 0.53 V Cr³⁺(aq) + 3e⁻ ⇄ Cr(s) E° = −0.74 V Overall reaction: 2Cr(s) + 3I₂(s) → 2Cr³⁺(aq) + (aq) + 6I⁻(aq)

Correct Answer
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Correct Answer
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Correct Answer
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If the equilibrium constant K_c is greater than 1 for a given reaction, predict the signs of ΔG° and E° at the same temperature.

Correct Answer
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A voltaic cell consists of a Mn/Mn²⁺ electrode (E° = −1.18 V) and a Fe/Fe²⁺ electrode (E° = −0.44 V) . Calculate [Fe²⁺] if [Mn²⁺] = 0.050 M and E_cell = 0.78 V at 25°C.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

What is the value of the equilibrium constant for the cell reaction below at 25°C? E°_cell = 0.61 V 2Cr(s) + 3Pb²⁺(aq) ⇄ 3Pb(s) + 2Cr³⁺(aq)

Correct Answer
verified

Calculate the potential of a voltaic cell (E°_cell) if it is required to do 5.43 × 10⁻³ kJ of work when a charge of 2.50 C is transferred.

Correct Answer
verified

Correct Answer
verified

A voltaic cell consists of an Au/Au³⁺ electrode (E° = 1.50 V) and a Cu/Cu²⁺ electrode (E° = 0.34 V) . Calculate [Au³⁺] if [Cu²⁺] = 1.20 M and E_cell = 1.13 V at 25°C.

Correct Answer
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Consider the following balanced redox reaction 3CuO(s) + 2NH₃(aq) → N₂(g) + 3H₂O(l) + 3Cu(s) Which of the following statements is true?

Correct Answer
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Examine the following half-reactions and select the strongest oxidizing agent among the species listed. Cr²⁺(aq) + 2e⁻⇄ Cr(s) E° = -0.913 V Fe²⁺(aq) + 2e⁻⇄ Fe(s) E° = -0.447 V Sr²⁺(aq) + 2e⁻⇄ Sr(s) E° = -2.89 V Co²⁺(aq) + 2e⁻⇄ Co(s) E° = -0.28 V

Correct Answer
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Correct Answer
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Consider the following redox equation Mn(OH) ₂(s) + MnO₄(aq) → MnO₄²⁻(aq) (basic solution) When the equation is balanced with smallest whole number coefficients, what is the coefficient for OH⁻(aq) and on which side of the equation is OH⁻(aq) present?

Correct Answer
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