Q: Which of the following reactions will produce a spontaneous electrochemical cell at 25°C? $$\text{Ag}^{+} + e^- \rightarrow \text{Ag} \quad E^\circ = +0.80\,\text{V}$$ $$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu} \quad E^\circ = +0.34\,\text{V}$$

$$\text{Ag} + \text{Cu}^{2+} \rightarrow \text{Ag}^{+} + \text{Cu}$$

Q: What is the cell potential ($$E_{cell}^\circ) $$for a voltaic cell constructed from the following half-reactions? $$\text{Zn}^{2+} + 2e^- \rightarrow \text{Zn} \quad E^\circ = -0.76\,\text{V}$$ $$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu} \quad E^\circ = +0.34\,\text{V}$$

$$E_{cell}^\circ = +1.10\,\text{V}$$

Q: Given the reaction $$\text{Fe}^{2+} + 2e^- \rightarrow \text{Fe}$$ ($$E^\circ = -0.44\,\text{V}) $$and $$\text{Ag}^{+} + e^- \rightarrow \text{Ag}$$ ($$E^\circ = +0.80\,\text{V}$$), what is the standard cell potential for the cell where Fe is the anode and Ag is the cathode?

$$E_{cell}^\circ = +1.24\,\text{V}$$

Q: Calculate the Gibbs free energy change ($$\Delta G^\circ) $$for a cell with $$E_{cell}^\circ = 1.10\,\text{V}$$ transferring 2 moles of electrons. ($$F = 96,485\,\text{C/mol})$$

$$\Delta G^\circ = -212,267\,\text{J}$$

Question 1

Which of the following metals is the strongest reducing agent based on the standard reduction potentials below?

$$	ext{Fe}^{2+} + 2e^- ightarrow 	ext{Fe} \quad E^\circ = -0.44\,	ext{V}$$
$$	ext{Cu}^{2+} + 2e^- ightarrow 	ext{Cu} \quad E^\circ = +0.34\,	ext{V}$$
$$	ext{Zn}^{2+} + 2e^- ightarrow 	ext{Zn} \quad E^\circ = -0.76\,	ext{V}$$
$$	ext{Ag}^{+} + e^- ightarrow 	ext{Ag} \quad E^\circ = +0.80\,	ext{V}$$

Accepted Answer

Zn

Question 2

In a galvanic cell, which of the following statements is true?

Accepted Answer

The cathode is where reduction occurs.

Question 3

Which of the following reactions will produce a spontaneous electrochemical cell at 25°C?

$$	ext{Ag}^{+} + e^- ightarrow 	ext{Ag} \quad E^\circ = +0.80\,	ext{V}$$
$$	ext{Cu}^{2+} + 2e^- ightarrow 	ext{Cu} \quad E^\circ = +0.34\,	ext{V}$$

Accepted Answer

$$	ext{Ag} + 	ext{Cu}^{2+} ightarrow 	ext{Ag}^{+} + 	ext{Cu}$$

Question 4

What is the cell potential ($$E_{cell}^\circ) $$for a voltaic cell constructed from the following half-reactions?

$$	ext{Zn}^{2+} + 2e^- ightarrow 	ext{Zn} \quad E^\circ = -0.76\,	ext{V}$$
$$	ext{Cu}^{2+} + 2e^- ightarrow 	ext{Cu} \quad E^\circ = +0.34\,	ext{V}$$

Accepted Answer

$$E_{cell}^\circ = +1.10\,	ext{V}$$

Question 5

In an electrolytic cell, which of the following is correct?

Accepted Answer

The anode is positive and oxidation occurs there.

Question 6

A reaction has a standard cell potential $$E_{cell}^\circ = -1.54\,	ext{V}. $$Which of the following statements is true?

Accepted Answer

The reaction is nonspontaneous and $$K \u003c 1.$$

Question 7

Which of the following best describes the function of a salt bridge in a galvanic cell?

Accepted Answer

It maintains electrical neutrality by allowing ion flow.

Question 8

Given the reaction $$	ext{Fe}^{2+} + 2e^- ightarrow 	ext{Fe}$$ ($$E^\circ = -0.44\,	ext{V}) $$and $$	ext{Ag}^{+} + e^- ightarrow 	ext{Ag}$$ ($$E^\circ = +0.80\,	ext{V}$$), what is the standard cell potential for the cell where Fe is the anode and Ag is the cathode?

Accepted Answer

$$E_{cell}^\circ = +1.24\,	ext{V}$$

Question 9

Which of the following will increase the mass of the cathode in an electrolytic cell?

Accepted Answer

Increasing the current passed through the cell.

Question 10

If a galvanic cell is constructed using $$	ext{Mg}^{2+} + 2e^- ightarrow 	ext{Mg}$$ ($$E^\circ = -2.37\,	ext{V}) $$and $$	ext{Cu}^{2+} + 2e^- ightarrow 	ext{Cu}$$ ($$E^\circ = +0.34\,	ext{V}$$), which metal will be oxidized?

Accepted Answer

Mg

Question 11

Calculate the Gibbs free energy change ($$\Delta G^\circ) $$for a cell with $$E_{cell}^\circ = 1.10\,	ext{V}$$ transferring 2 moles of electrons. ($$F = 96,485\,	ext{C/mol})$$

Accepted Answer

$$\Delta G^\circ = -212,267\,	ext{J}$$

Question 12

Which of the following is true for a spontaneous electrochemical reaction?

Accepted Answer

$$E_{cell}^\circ \u003e 0$$, $$\Delta G^\circ  1$$

Question 13

What is the Nernst equation for calculating the cell potential at nonstandard conditions?

Accepted Answer

$$E_{cell} = E_{cell}^\circ - \frac{0.0592}{n} \log Q$$

Question 14

A cell notation is given as $$	ext{Zn} | 	ext{Zn}^{2+} (1.0\,	ext{M}) || 	ext{Cu}^{2+} (1.0\,	ext{M}) | 	ext{Cu}. $$Which direction do electrons flow?

Accepted Answer

From Zn to Cu

Question 15

If 1.5 A of current is passed for 72 hours to reduce Cu$$^{2+} to Cu(s$$), how many grams of copper are deposited? ($$F = 96,485\,	ext{C/mol}$$, MW of Cu = 63.55 g/mol)

Accepted Answer

26.7 g

Question 16

Which of the following statements is true about the salt bridge in an electrochemical cell?

Accepted Answer

It allows the migration of ions to maintain charge balance.

Question 17

What is the equilibrium constant $$K$$ for a cell reaction at 25°C with $$E_{cell}^\circ = 0.59\,	ext{V}$$ and $$n = 2$$?

Accepted Answer

$$K = 1.0 	imes 10$$^{20}$$

Question 18

Which of the following is the correct cell notation for a cell where the following reaction occurs?
$$3	ext{Sn}^{2+} (aq) + 2	ext{Al} (s) ightarrow 3	ext{Sn} (s) + 2	ext{Al}^{3+} (aq)$$

Accepted Answer

$$	ext{Al} (s) | 	ext{Al}^{3+} (aq) || 	ext{Sn}^{2+} (aq) | 	ext{Sn} (s)$$

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