Question 1

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

Accepted Answer

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

Question 2

In the reaction $$\mathrm{Zn(s) + Cu$$^{2+}$$(aq) \rightarrow Zn$$^{2+}$$(aq) + Cu(s)}$$, which species is oxidized?

Accepted Answer

Zn(s)

Question 3

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

Accepted Answer

$$E^\circ_{cell} = 0.34 - (-0.76) = 1.10\,V$$

Question 4

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

Accepted Answer

$$\Delta G^\circ  0$$, $$K \u003e 1$$

Question 5

A battery converts chemical energy into electrical energy. Which process occurs at the anode of a typical voltaic cell?

Accepted Answer

Oxidation

Question 6

What is the oxidation state of oxygen in $$\mathrm{Na_2O_2}$$?

Accepted Answer

$$-1$$

Question 7

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

Accepted Answer

$$E^\circ_{cell} = \frac{0.0592\,V}{n} \log K$$

Question 8

In a concentration cell, electrons flow from:

Accepted Answer

The electrode in the less concentrated solution to the more concentrated solution

Question 9

Which of the following statements about the standard hydrogen electrode (SHE) is correct?

Accepted Answer

It is used as a reference to measure other half-cell potentials

Question 10

If the cell potential ($$E^\circ_{cell}) $$for a reaction is negative, what can be concluded about the reaction?

Accepted Answer

The reaction is non-spontaneous under standard conditions

Question 11

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

Accepted Answer

$$\mathrm{Zn(s) | Zn$$^{2+}$$(aq) || Cu$$^{2+}$$(aq) | Cu(s)}$$

Question 12

Which of the following is NOT a characteristic of an inert platinum electrode in a voltaic cell?

Accepted Answer

It participates in the cell reaction

Question 13

What is the relationship between $$\Delta G^\circ$$ and $$E^\circ_{cell}$$?

Accepted Answer

$$\Delta G^\circ = -nFE^\circ_{cell}$$

Question 14

Which of the following best describes the flow of electrons in a voltaic cell?

Accepted Answer

Electrons flow from the anode to the cathode

Question 15

A student mixes $$\mathrm{Fe$$^{2+}$$}$$ and $$\mathrm{$$MnO_4$$^-} in $$acidic solution. Which half-reaction occurs at the cathode?

Accepted Answer

$$\mathrm{$$MnO_4$$^-} + 5e^- + 8H^+ \rightarrow Mn$$^{2+}$$ + 4H_2O}$$

Question 16

Which of the following is a correct statement about oxidation states?

Accepted Answer

Free elements in their atomic state always have an oxidation number of $$0$$

Question 17

In a battery, which component is typically the reducing agent?

Accepted Answer

The anode

Question 18

Which formula is used to calculate the cell potential under non-standard conditions?

Accepted Answer

$$E_{cell} = E^\circ_{cell} - \frac{0.0592\,V}{n} \log Q$$

Question 19

A battery is used to power a smartphone. Which energy transformation occurs in the battery?

Accepted Answer

Chemical energy is converted to electrical energy

Electrochemistry: Principles, Cells, and Applications

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