Answer the following questions related to the given electrochemical cell. 1. Ans

Question

Answer the following questions related to the given electrochemical cell.

1. Answer the following questions under standard conditions

(a) The half-cell containing Ce3+/Ce4+ is the cathode .

(b) The half-cell containing H+/H2 is the anode .

(c) What is E°cell (in V)? Report your answer to three decimal places in standard notation (i.e., 0.123 V). 1.720 V

2. (a) Which one of the following balanced chemical reactions describes the process occurring in the electrochemical cell?
Incorrect: 2Ce4+(aq) + 2H2(g) 4H+(aq) + 2Ce3+(aq).
Incorrect: 2H+(aq) + 2Ce3+(aq) 2Ce4+(aq) + H2(g).
Incorrect: 4H+(aq) + 2Ce3+(aq) 2Ce4+(aq) + 2H2(g).
Correct: 2Ce4+(aq) + H2(g) 2H+(aq) + 2Ce3+(aq).

(b) What is G° (in kJ/mol) for the process that is occurring in the electrochemical cell? Report your answer to three significant figures in scientific notation (i.e., 1.23e2 kJ/mol). -3.32×102kJ/mol

3. The electrochemical cell is comprised of a Pt electrode in a 6.04 × 10-1 M solution of Ce4+ and 2.63 × 10-1 M solution of Ce3+ coupled to a Pt electrode where the [H+] is 5.67 × 10-3 M and the partial pressure of H2(g) is 1.290 atm. The temperature of this cell is held constant at 298.15 K

(a) Under these conditions, the half-cell containing Ce3+ and Ce4+ is the  anode cathode  .

(b) Under these conditions, the half-cell containing H+ and H2 is the  anode cathode  .

(c) What is Ecell (in V) for this electrochemical cell? Report your answer to three decimal places in standard notation (i.e., 0.123 V).

4. Answer the following questions under the conditions described in question 3.

(a) Which one of the following balanced chemical reactions describes the process occurring in the electrochemical cell?
4H+(aq) + 2Ce3+(aq) 2Ce4+(aq) + 2H2(g).
2H+(aq) + 2Ce3+(aq) 2Ce4+(aq) + H2(g).
2Ce4+(aq) + 2H2(g) 4H+(aq) + 2Ce3+(aq).
2Ce4+(aq) + H2(g) 2H+(aq) + 2Ce3+(aq).

(b) What is the value of G (in kJ/mol) for the process occurring in this electrochemical cell under the conditions described in Part B? Report your answer to three significant figures in scientific notation (i.e., 1.23e2 kJ/mol).

Explanation / Answer

3.

a) cathode

b) anode

c) Ecell = E0cell - RT/nFln((H+)^2*(Ce3+)^2/pH2*(Ce^4+)^2)

          = 1.720 - (8.314*298.15/(2*96500))ln((5.67*10^-3)^2*(2.63*10^-1)/(1.29*0.0263))

          = 1.826 v

4.

2Ce4+(aq) + H2(g) ---> 2H+(aq) + 2Ce3+(aq).

DG = -nFEcell

   = -2*96500*1.826

    = -352.418 kj

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