Question 1

Chromium metal is electroplated from acidic aqueous solutions containing the dichromate ion, Cr2O72-. What is the minimum time needed to plate out 10.0 g of chromium metal from such a solution, if the current is 50.0 A?

Accepted Answer

A)   6.2 minutes
B)   12.4 minutes
C)   18.6 minutes
D)   24.7 minute
E)   37.1 minutesF) C) and D)
G) B) and D)

Question 2

What mass of silver will be formed when 15.0 A are passed through molten AgCl for 25.0 minutes?

Accepted Answer

A)   0.419 g
B)   6.29 g
C)   12.6 g
D)   25.2 g
E)   33.4 gF) None of the above
G) A) and D)

Question 3

When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be ______. 
Al(s)  + HSO4-(aq)  + OH-(aq)   Al2O3(s)  + S2-(aq)  + H2O(l)

Accepted Answer

A)   1
B)   3
C)   4
D)   8
E)   none of the aboveF) A) and C)
G) A) and B)

Question 4

Given that E° for X + e-  Y is greater than E° for A + 2e-  B, it is correct to say that, under standard conditions

Accepted Answer

A)   X will oxidize A.
B)   Y will oxidize A.
C)   Y will reduce A.
D)   B will oxidize X.
E)   B will reduce X.F) B) and C)
G) A) and E)

Question 5

In the electrolyte of an electrochemical cell, current is carried by electrons moving from the anode to the cathode.

Accepted Answer

A) True 
 B)False

Question 6

The value of the equilibrium constant for the reaction of nickel(II)  ions with cadmium metal is 1.17 × 105. Calculate G° for the reaction at 25°C.

Accepted Answer

A)   -12.6 kJ
B)   -28.9 kJ
C)   12.6 kJ
D)   28.9 kJ
E)   none of the aboveF) B) and C)
G) B) and D)

Question 7

Calculate E°cell for the reaction of nickel(II)  ions with cadmium metal at 25°C. K = 1.17 × 105
 Ni2+(aq)  + Cd(s)   Cd2+(aq)  + Ni(s)

Accepted Answer

A)   0.075 V
B)   0.10 V
C)   0.12 V
D)   0.15 V
E)   0.30 VF) All of the above
G) B) and C)

Question 8

A concentration cell consists of two Al/Al3+electrodes. The electrolyte in compartment A is 0.050 M Al(NO3) 3 and in compartment B is 1.25 M Al(NO3) 3. What is the voltage of the cell at 25°C?

Accepted Answer

A)   0.083 V
B)   0.062 V
C)   0.041V
D)   0.028 V
E)   none of the aboveF) A) and B)
G) A) and C)

Question 9

Which component of the following cell notation is the anode? P | Q || R | S

Accepted Answer

A)   P
B)   Q
C)   R
D)   S
E)   One of the | symbols is the anode.F) C) and D)
G) B) and E)

Question 10

Consider the reaction in the lead-acid cell 
Pb(s)  + PbO2(s)  + 2H2SO4(aq)   2PbSO4(aq)  + 2H2O(l) 
For which E°cell = 2.04 V at 298 K. G° for this reaction is

Accepted Answer

A)   -3.94 × 105 kJ.
B)   -3.94 × 102 kJ.
C)   -1.97 × 105 kJ.
D)   -7.87 × 102 kJ.
E)   none of the above.F) A) and C)
G) B) and D)

Question 11

Write down equations representing the anode half-reaction, the cathode half-reaction, and the overall cell reaction for the lead-acid battery.

Accepted Answer

Anode half-reaction: Pb(s) + SO₄^2-(aq) F1F1...

Question 12

Which of the following statements about voltaic and electrolytic cells is correct?

Accepted Answer

A)   The electrons in the external wire flow from cathode to anode in both types of cell.
B)   Oxidation occurs at the cathode only in a voltaic cell.
C)   The free energy change, G, is negative for an electrolytic cell.
D)   The cathode is labeled as positive (+)  in a voltaic cell but negative (-)  in an electrolytic cell.
E)   Reduction occurs at the anode in an electrolytic cell.F) A) and D)
G) None of the above

Question 13

The voltaic cell made up of cobalt, copper, and their M2+ ions, has E°cell = 0.62 V. If E° of the cathode half-cell is 0.34 V, what is E° of the anode half-cell? 
Cu2+(aq)  + Co(s)   Cu(s)  + Co2+(aq)

Accepted Answer

A)   -0.28 V
B)   -0.96 V
C)   0.28 V
D)   0.96 V
E)   none of the aboveF) B) and D)
G) C) and D)

Question 14

Which one of the following statements about electrochemical cells is correct?

Accepted Answer

A)   In a salt bridge, current is carried by cations moving toward the anode, and anions toward the cathode.
B)   In the external wire, electrons travel from cathode to anode.
C)   The anode of a voltaic cell is labeled minus (-) .
D)   Oxidation occurs at the cathode, in an electrolytic cell.
E)   None of the above statements is correct.F) A) and E)
G) B) and C)

Question 15

Explain what is meant by a fuel cell. Provide a balanced equation to represent the reaction in any fuel cell of your choice.

Accepted Answer

A fuel cell is a voltaic cell in which t...

Question 16

A voltaic cell prepared using aluminum and nickel has the following cell notation. 
Al(s)  | Al3+(aq)  || Ni2+(aq)  | Ni(s) 
Which of the following represents the correctly balanced spontaneous reaction equation for the cell?

Accepted Answer

A)   Ni2+(aq)  + Al(s)   Al3+(aq)  + Ni(s) 
B)   3Ni2+(aq)  + 2Al(s)   2Al3+(aq)  + 3Ni(s) 
C)   Ni(s)  + Al3+(aq)   Ni2+(aq)  + Al(s) 
D)   3Ni(s)  + 2Al3+(aq)   3Ni2+(aq)  + 2Al(s) 
E)   none of the aboveF) B) and E)
G) A) and B)

Question 17

Which one of the following is not a redox reaction?

Accepted Answer

A)   Al(OH) 4-(aq)  + 4H+(aq)   Al3+(aq)  + 4H2O(l) 
B)   C6H12O6(s)  + 6O2(g)   6CO2(g)  + 6H2O(l) 
C)   Na6FeCl8(s)  + 2Na(l)   8NaCl(s)  + Fe(s) 
D)   2H2O2(aq)   2H2O(l)  + O2(g) 
E)   CO2(g)  + H2(g)   CO(g)  + H2O(g) F) D) and E)
G) A) and B)

Question 18

Which of the following elements can be isolated by electrolysis of the aqueous salt shown?

Accepted Answer

A)   phosphorus from K3PO4(aq) 
B)   sodium from NaBr(aq) 
C)   aluminum from AlCl3(aq) 
D)   fluorine from KF(aq) 
E)   iodine from NaI(aq) F) A) and B)
G) A) and C)

Question 19

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) B) and E)
G) A) and B)

Question 20

For the reaction occurring in a voltaic (galvanic) cell, F1F1F1S1F1F1F10G > 0.

Accepted Answer

A) True 
 B)False

Exam 21: Electrochemistry: Chemical Change and Electrical Work

In the electrolyte of an electrochemical cell, current is carried by electrons moving from the anode to the cathode.

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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be ______. Al(s) + HSO4-(aq) + OH-(aq)  Al2O3(s) + S2-(aq) + H2O(l)

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For the reaction occurring in a voltaic (galvanic) cell, G > 0.

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Given that E° for X + e-  Y is greater than E° for A + 2e-  B, it is correct to say that, under standard conditions

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Calculate E°cell for the reaction of nickel(II) ions with cadmium metal at 25°C. K = 1.17 × 105 Ni2+(aq) + Cd(s)  Cd2+(aq) + Ni(s)

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Which of the following elements can be isolated by electrolysis of the aqueous salt shown?

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Consider the reaction in the lead-acid cell Pb(s) + PbO2(s) + 2H2SO4(aq)  2PbSO4(aq) + 2H2O(l) For which E°cell = 2.04 V at 298 K. G° for this reaction is

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Which one of the following is not a redox reaction?

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The voltaic cell made up of cobalt, copper, and their M2+ ions, has E°cell = 0.62 V. If E° of the cathode half-cell is 0.34 V, what is E° of the anode half-cell? Cu2+(aq) + Co(s)  Cu(s) + Co2+(aq)

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A concentration cell consists of two Al/Al3+electrodes. The electrolyte in compartment A is 0.050 M Al(NO3) 3 and in compartment B is 1.25 M Al(NO3) 3. What is the voltage of the cell at 25°C?

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A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s) | Al3+(aq) || Ni2+(aq) | Ni(s) Which of the following represents the correctly balanced spontaneous reaction equation for the cell?

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Chromium metal is electroplated from acidic aqueous solutions containing the dichromate ion, Cr2O72-. What is the minimum time needed to plate out 10.0 g of chromium metal from such a solution, if the current is 50.0 A?

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Which one of the following statements about electrochemical cells is correct?

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Explain what is meant by a fuel cell. Provide a balanced equation to represent the reaction in any fuel cell of your choice.

Correct AnswerverifiedA fuel cell is a voltaic cell in which t...View AnswerShow Answer

Which of the following statements about voltaic and electrolytic cells is correct?

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Which component of the following cell notation is the anode? P | Q || R | S

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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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What mass of silver will be formed when 15.0 A are passed through molten AgCl for 25.0 minutes?

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The value of the equilibrium constant for the reaction of nickel(II) ions with cadmium metal is 1.17 × 105. Calculate G° for the reaction at 25°C.

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Write down equations representing the anode half-reaction, the cathode half-reaction, and the overall cell reaction for the lead-acid battery.

Correct AnswerverifiedAnode half-reaction: Pb(s) + SO42-(aq) F1F1...View AnswerShow Answer

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When the following redox equation is balanced with smallest whole number coefficients, the coefficient for the hydrogen sulfate ion will be ______. Al(s) + HSO₄^-(aq) + OH^-(aq)  Al₂O₃(s) + S^2-(aq) + H₂O(l)

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Given that E° for X + e^-  Y is greater than E° for A + 2e^-  B, it is correct to say that, under standard conditions

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Calculate E°_cell for the reaction of nickel(II) ions with cadmium metal at 25°C. K = 1.17 × 10⁵ Ni²⁺(aq) + Cd(s)  Cd²⁺(aq) + Ni(s)

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Correct Answer
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Consider the reaction in the lead-acid cell Pb(s) + PbO₂(s) + 2H₂SO₄(aq)  2PbSO₄(aq) + 2H₂O(l) For which E°_cell = 2.04 V at 298 K. G° for this reaction is

Correct Answer
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Correct Answer
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The voltaic cell made up of cobalt, copper, and their M²⁺ ions, has E°_cell = 0.62 V. If E° of the cathode half-cell is 0.34 V, what is E° of the anode half-cell? Cu²⁺(aq) + Co(s)  Cu(s) + Co²⁺(aq)

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A concentration cell consists of two Al/Al³⁺electrodes. The electrolyte in compartment A is 0.050 M Al(NO₃) ₃and in compartment B is 1.25 M Al(NO₃) ₃. What is the voltage of the cell at 25°C?

Correct Answer
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A voltaic cell prepared using aluminum and nickel has the following cell notation. Al(s) | Al³⁺(aq) || Ni²⁺(aq) | Ni(s) Which of the following represents the correctly balanced spontaneous reaction equation for the cell?

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Chromium metal is electroplated from acidic aqueous solutions containing the dichromate ion, Cr₂O₇^2-. What is the minimum time needed to plate out 10.0 g of chromium metal from such a solution, if the current is 50.0 A?

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Correct Answer
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Correct Answer
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A fuel cell is a voltaic cell in which t...
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The value of the equilibrium constant for the reaction of nickel(II) ions with cadmium metal is 1.17 × 10⁵. Calculate G°for the reaction at 25°C.

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Correct Answer
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Anode half-reaction: Pb(s) + SO₄^2-(aq) F1F1...
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