Question

# 1. A chemist proposes a new kind of battery in which methane (CH4) is oxidized to CO2, while iodine (I2) is

reduced to iodide (I- ) in acidic aqueous solution.

a) Write out the two balanced half reactions taking place in this cell.

b) Write out the balanced overall reaction taking place in this cell.

2. Consider the galvanic cell: Cu (s) | Cu2+ (aq, 0.448 mol L-1 ) || Cr2O7 2- (aq, 0.120 mol L-1 ), Cr3+ (aq, 0.120 mol L-1 ), H + (aq, 1.00 mol L-1 ) | Pt (s)

a) Write out the overall reaction taking place in this cell.

b) Calculate E°cell for this cell at 298 K to two decimal places.

c) Calculate Ecell for this cell at 298 K to two decimal places.

3. Consider a chemical reaction that has ΔrH° = -397.3 kJ mol-1 and an equilibrium constant of 6.5 x 1091 at 298 K. What is the equilibrium constant of the same reaction if the temperature is raised to 175°C?

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