Electrochemistry

Al³⁺(aq) + 3e^-→Al(s) E° = -1.66 V

Ag⁺(aq) + e^-→Ag(s) E° = +0.80 V

According to the standard reduction potentials given above, what is the standard cell potential for the reaction represented below?

3Ag⁺(aq) + Al(s) →3Ag(s) + Al³⁺(aq)

• -1.74 V

• -0.86 V

• +1.74 V

• +2.46 V

Tags

NGSS.HS-PS3-1

An electric current of 1.00 ampere is passed through an aqueous solution of Ni(NO₃)₂. How long will it take to plate out exactly 1.00 mol of nickel metal, assuming 100 percent current efficiency?

(1 Faraday = 96,500 coulombs)

• 386,000 sec

• 193,000 sec

• 96,500 sec

• 48,200 sec

Cu(s) + 2Ag⁺ →Cu²⁺ + 2Ag(s)

If the equilibrium constant for the reaction above is 3.7 x 10¹⁵, which of the following correctly describes the standard voltage, E°, and the standard free energy change, ΔG°, for this reaction?

• E° is positive and ΔG° is negative.

• E° is negative and ΔG° is positive.

• E° and ΔG° are both positive.

• E° and ΔG° are both negative.

Tags

NGSS.HS-PS1-4

Cu²⁺(aq) + 2e^-→Cu(s) E° = 0.34 V

Cr³⁺(aq) + e^-→Cr²⁺(aq) E° = -0.41 V

• Cu²⁺(aq) + Cr³⁺(aq) → Cu(s) + Cr²⁺(aq)

• Cu²⁺(aq) + 2Cr²⁺(aq) → Cu(s) + 2Cr³⁺(aq)

• Cu(s) + 2Cr³⁺(aq) → Cu²⁺(aq) + 2Cr²⁺(aq)

• Cu(s) + Cr³⁺(aq) → Cu²⁺(aq) + Cr²⁺(aq)

Tags

NGSS.HS-PS1-2

For the construction of a second galvanic cell (not shown), only one modification was made to the galvanic cell illustrated above: the Cu electrode has double the mass of the Cu electrode. Which of the following correctly compares the initial E° for the second cell to that of first cell at 298K, and why?

• The initial E° for the second cell is twice that of the first cell because a larger amount of Cu(s) can be oxidized to Cu²⁺.

• The initial E° for the second cell is twice that of the first cell because more Cu²⁺ ions can be deposited on the solid Cu electrode.

• The initial E° for the second cell is half that of the first cell because the greater amount of Cu(s) in the half-cell inhibits the formation of more Cu(s).

• The initial E° for the second cell is same as for the first cell because the overall chemical reaction that occurs in the cell does not change.

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-4

NGSS.HS-PS1-7

This diagram above shows the apparatus used for the electrolysis of CuCl₂(aq) according to the chemical equation given. Which of the following mathematical expressions can be used to calculate the current required to produce 0.125 mol of Cu(s) in 1 hour?

• $I\ =\ \left(\frac{2\times0.125\times96,485}{3,600}\right)$

• $I=\left(\frac{2\times0.125\times96,485}{1}\right)$

• $I\ =\ \left(\frac{0.125\times96,485}{3,600}\right)$

• $I=\left(\frac{0.125\times96,485}{1}\right)$

Tags

NGSS.HS-PS2-5

The diagram above represents an electrolytic cell in which the reaction 2 NaCl(l) →2 Na(l) +Cl₂(g) takes place. The table gives the relevant reduction half-reactions and the standard reduction potentials. Based on the information given, which of the following is true?

• The operation of the cell generates a potential of 1.35 V because the reaction is thermodynamically favorable.

• The operation of the cell generates a potential of 5.43 V because the reaction is thermodynamically favorable.

• The operation of the cell requires at least 4.07 V to be supplied because the reaction is not thermodynamically favorable.

• The operation of the cell requires at least 2.72 V to be supplied because the reaction is not thermodynamically favorable.

Tags

NGSS.HS-PS1-4

M(s) + 3Ag⁺(aq) →3Ag(s) + M³⁺(aq) E° = +2.46 V

Ag⁺(aq) + e^-→Ag(s) E° = +0.80 V

According to the information above, what is the standard reduction potential for the half-reaction M³⁺(aq) + 3e^-→M(s)?

• -1.66 V

• -0.06 V

• 0.06 V

• 1.66 V

A current of 0.80 ampere is supplied to AgNO₃(aq) for 30.0 minutes. Which of the following equations can be used to calculate the approximate mass of Ag(s) deposited on the object?

• $\left(\frac{0.80\times30.0\times60}{96,485\times107.9}\right)$

• $\left(\frac{0.80\times30.0\times60\times96.485}{107.9}\right)$

• $\left(\frac{0.80\times30.0\times60\times107.9}{96,485}\right)$

• $\left(\frac{0.80\times30.0\times107.9}{96,485}\right)$

Tags

NGSS.HS-PS3-1

The galvanic cell shown above generates a cell potential of +3.17 V when operated under standard conditions. A second galvanic cell is made from the same two metals, and the measured cell potential is +3.25 V. Which of the following could be the reason for the second cell having a greater cell potential?

• The mass of the Ag electrode in the second cell is greater than in first, resulting in a reduction potential greater than 0.80 V.

• The mass of the Mg electrode in the second cell is smaller than in first, resulting in a reduction potential lower than -2.37 V.

• [Mg²⁺] > 1 M and [Ag⁺] = 1 M in the second cell, resulting in Q > 1, and Q = 1 for the first cell.

• [Ag⁺] > 1 M and [Mg²⁺] = 1 M in the second cell, resulting in Q < 1, and Q = 1 for the first cell.

Tags

NGSS.HS-PS1-5

NGSS.HS-PS3-5