Question 1

Which statement correctly describes the difference between a galvanic (voltaic) cell and an electrolytic cell?

Accepted Answer

In a galvanic cell, electricity is generated by a spontaneous redox reaction and $$E_{cell} \u003e 0.$$

Question 2

What is the function of the salt bridge in an electrochemical cell?

Accepted Answer

It maintains electrical neutrality by allowing ions to migrate between half-cells.

Question 3

Given the cell notation $$\mathrm{Cu(s) | Cu$$^{2+}$$(aq) || Ag$$^{+}$$(aq) | Ag(s)}$$, which half-cell undergoes reduction?

Accepted Answer

Ag$$^{+}(aq$$) | Ag(s)

Question 4

Which of the following correctly represents the standard hydrogen electrode (SHE)?

Accepted Answer

$$\mathrm{2H^+(aq, 1\ M) + 2e^- \rightarrow H_2$(g, 1\ atm)}$$

Question 5

If the standard reduction potentials are $$E^	ext{o}_{Zn$$^{2+}$$/Zn} = -0.76\ V$$ and $$E^	ext{o}_{Cu$$^{2+}$$/Cu} = +0.34\ V$$, what is the standard cell potential for a cell made of these two half-cells?

Accepted Answer

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

Question 6

Which of the following statements about standard electrode potentials is correct?

Accepted Answer

A more positive $$E^	ext{o}$$ value means the species is more likely to be reduced.

Question 7

For the reaction $$\mathrm{Zn(s) + Cl_2$(g) \rightarrow Zn$$^{2+}$$(aq) + 2Cl^-(aq)}$$, given $$E^	ext{o}_{Zn$$^{2+}$$/Zn} = -0.76\ V$$ and $$E^	ext{o}_{Cl_2$/Cl^-} = +1.36\ V$$, calculate the standard cell potential.

Accepted Answer

$$E^	ext{o}_{cell} = +2.12\ V$$

Question 8

Which of the following reactions will occur spontaneously under standard conditions?

Accepted Answer

A cell with $$E^	ext{o}_{cell} \u003e 0$$

Question 9

If $$E^	ext{o}_{Fe$$^{3+}$$/Fe^{2+}$$} = +0.77\ V$$ and E^	$$ext{o}_{$$I_2/I$$^-} = +0.54\ V$$, can Fe$$^{3+}$$ oxidize I$$^-$$ to I_2$ under standard conditions?

Accepted Answer

Yes, because $$E^	ext{o}_{cell} \u003e 0$$

Question 10

Which equation correctly relates the standard cell potential to the equilibrium constant $$K$$?

Accepted Answer

$$E^	ext{o}_{cell} = \dfrac{RT}{nF} \ln K$$

Question 11

A cell is constructed with $$[Cu$$^{2+}$$] = 2.0\ M$$ and $$[Zn$$^{2+}$$] = 0.10\ M. If$$ $$E^	ext{o}_{cell} = 1.10\ V$$, what is the cell potential at $$25^\circ C$$? (Use the Nernst equation: $$E_{cell} = E^	ext{o}_{cell} - \dfrac{0.0257}{n} \ln Q)$$

Accepted Answer

$$E_{cell} = 1.14\ V$$

Question 12

Which of the following is true about the relationship between Gibbs free energy and cell potential?

Accepted Answer

$$\Delta G = -nFE_{cell}$$

Question 13

During electrolysis, which statement is correct regarding the mass of substance produced at an electrode?

Accepted Answer

It is directly proportional to the quantity of charge passed.

Question 14

A current of $$0.452\ A is $$passed through molten $$CaCl_2$$ for $$1.50$$ hours. How many moles of electrons are transferred? ($$F = 96485\ C/mol)$$

Accepted Answer

$$0.0253\ mol$$

Question 15

In the electrolysis of molten $$CaCl_2$$, what is the half-reaction occurring at the cathode?

Accepted Answer

$$Ca^{2+}(aq) + 2e$$^- \rightarrow Ca(s)$$

Question 16

Which industrial process uses electrolysis for the purification of metals?

Accepted Answer

Electrorefining

Question 17

If $$Q = I 	imes t$$, what is the total charge passed when a current of $$2.0\ A$$ flows for $$30$$ minutes?

Accepted Answer

$$3600\ C$$

Question 18

Which of the following best describes the role of Faraday's constant in electrochemistry?

Accepted Answer

It is the charge carried by one mole of electrons.

Question 19

A cell is constructed with $$[Cr$$^{3+}$$] = 0.0100\ M$$ and $$[Zn$$^{2+}$$] = 5.30\ M. If$$ $$E^	ext{o}_{Cr$$^{3+}$$/Cr} = -0.74\ V$$ and $$E^	ext{o}_{Zn$$^{2+}$$/Zn} = -0.76\ V$$, what is the cell potential at $$25^\circ C$$? (Use $$E_{cell} = E^	ext{o}_{cell} - \dfrac{0.0257}{n} \ln Q)$$

Accepted Answer

$$E_{cell} \approx -0.08\ V$$

Electrochemistry: Principles, Cells, and Applications

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