Question 1

Which of the following best describes the standard cell potential ($$E^	ext{cell}_{	ext{std}}) $$for an electrochemical cell?

Accepted Answer

It is the difference between the reduction potential of the cathode and the anode.

Question 2

Given the following half-reactions and their standard reduction potentials:

$$\mathrm{Fe$$^{3+}$$ + e^- \rightarrow Fe$$^{2+}$$}$$  $$E^	ext{std} = +0.77\ \mathrm{V}$$
$$\mathrm{Li^+ + e^- \rightarrow Li}$$  $$E^	ext{std} = -3.04\ \mathrm{V}$$

What is the standard cell potential ($$E^	ext{cell}_{	ext{std}}) $$for a cell where lithium is the anode and iron(III) is the cathode?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +2.27\ \mathrm{V}$$

Question 3

Which equation is used to calculate the standard cell potential ($$E^	ext{cell}_{	ext{std}}) $$from standard reduction potentials?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = E^	ext{red}_{	ext{cathode}} - E^	ext{red}_{	ext{anode}}$$

Question 4

If the calculated $$E^	ext{cell}_{	ext{std}}$$ for a reaction is positive, what does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous under standard conditions.

Question 5

A cell is constructed using the following half-reactions:

$$\mathrm{Ag^+ + e^- \rightarrow Ag}$$  $$E^	ext{std} = +0.80\ \mathrm{V}$$
$$\mathrm{Cu$$^{2+}$$ + 2e^- \rightarrow Cu}$$  $$E^	ext{std} = +0.34\ \mathrm{V}$$

Which metal acts as the anode?

Accepted Answer

Copper ($$\mathrm{Cu})$$

Question 6

For the reaction $$\mathrm{Zn$$^{2+}$$ + 2e^- \rightarrow Zn}$$ ($$E^	ext{std} = -0.76\ \mathrm{V}) $$and $$\mathrm{Cu$$^{2+}$$ + 2e^- \rightarrow Cu}$$ ($$E^	ext{std} = +0.34\ \mathrm{V}$$), what is the standard cell potential for a cell with zinc as the anode and copper as the cathode?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +1.10\ \mathrm{V}$$

Question 7

Which of the following statements is TRUE regarding the assignment of cathode and anode in a voltaic cell?

Accepted Answer

The cathode is where reduction occurs and electrons are gained.

Question 8

A student constructs a cell using $$\mathrm{Fe$$^{3+}$$/Fe^{2+}$$}$$ (E^	$$ext{std} = +0.77\ \mathrm{V}$$) and $$\mathrm{Ag^+/Ag}$$ (E^	$$ext{std} = +0.80\ \mathrm{V}$$). What is the E^	$$ext{cell}_{	ext{std}}$ and which reaction occurs at the cathode?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +0.03\ \mathrm{V}$$; Ag is reduced at the cathode.

Question 9

Which of the following best explains why the standard cell potential is independent of the stoichiometric coefficients in the half-reactions?

Accepted Answer

Because the cell potential is an intensive property and does not depend on the amount of substance.

Question 10

If a cell is constructed with $$\mathrm{Li^+/Li}$$ ($$E^	ext{std} = -3.04\ \mathrm{V}) $$and $$\mathrm{Ag^+/Ag}$$ ($$E^	ext{std} = +0.80\ \mathrm{V}$$), what is the $$E^	ext{cell}_{	ext{std}}$$ and is the reaction spontaneous?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +3.84\ \mathrm{V}$$; spontaneous

Question 11

Which of the following is the correct cell notation for a cell with zinc as the anode and copper as the cathode?

Accepted Answer

$$\mathrm{Zn | Zn$$^{2+}$$ || Cu$$^{2+}$$ | Cu}$$

Question 12

A cell is constructed using $$\mathrm{Fe$$^{3+}$$/Fe^{2+}$$}$$ (E^	$$ext{std} = +0.77\ \mathrm{V}$$) and $$\mathrm{$$Cu^{2+}/Cu$$}$$ (E^	$$ext{std} = +0.34\ \mathrm{V}$$). What is the E^	$$ext{cell}_{	ext{std}}$ and which species is oxidized?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +0.43\ \mathrm{V}$$; $$Fe^{2+} is $$oxidized.

Question 13

Which of the following half-reactions would be most likely to occur at the cathode in a cell with the highest possible standard cell potential?

Accepted Answer

$$\mathrm{Ag^+ + e^- \rightarrow Ag}$$ ($$E^	ext{std} = +0.80\ \mathrm{V})$$

Question 14

A cell is constructed using $$\mathrm{Fe$$^{3+}$$/Fe^{2+}$$}$$ (E^	$$ext{std} = +0.77\ \mathrm{V}$$) and $$\mathrm{Li^+/Li}$$ (E^	$$ext{std} = -3.04\ \mathrm{V}$$). What is the E^	$$ext{cell}_{	ext{std}}$ and which direction do electrons flow?

Accepted Answer

$$E^	ext{cell}_{	ext{std}} = +3.81\ \mathrm{V}$$; from Li to $$Fe^{3+}$

Question 15

Which of the following is a correct interpretation of the sign of $$E^	ext{cell}_{	ext{std}} in $$terms of spontaneity?

Accepted Answer

A positive $$E^	ext{cell}_{	ext{std}}$$ means the reaction is spontaneous.

Question 16

In a cell constructed from $$\mathrm{Ag^+/Ag}$$ and $$\mathrm{Cu$$^{2+}$$/Cu}$$, which metal will be plated out if the cell is allowed to run?

Accepted Answer

Silver ($$\mathrm{Ag})$$

Question 17

A cell is constructed using $$\mathrm{Fe$$^{3+}$$/Fe^{2+}$$}$$ (E^	$$ext{std} = +0.77\ \mathrm{V}$$) and $$\mathrm{Ag^+/Ag}$$ (E^	$$ext{std} = +0.80\ \mathrm{V}$). Predict whether the reaction as written will occur spontaneously.

Accepted Answer

Yes, because $$E^	ext{cell}_{	ext{std}} is $$positive.

Question 18

Which of the following best describes the role of the salt bridge in a voltaic cell?

Accepted Answer

It maintains electrical neutrality by allowing ion flow.

Standard Cell Potential and Electrochemistry Study Notes

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