Luke Skywalker found that the batteries for his lightsaber were running low. A cryptic inscription on the handle translated roughly into "Four AA dark-side batteries required." The total voltage produced by the four 1.50 V batteries in series therefore was 6.00 volts. If the cell reaction transfers one electron for each mole of the reactants, what is the Gibbs free-energy change for the redox reaction in each of Luke's batteries?

Question

Quizplus · Accepted Answer

The voltage produced by each AA battery is 1.50 V. Therefore, the total voltage produced by four AA batteries in series is 6.00 V. Since the cell reaction transfers one electron for each mole of the reactants, the Gibbs free-energy change can be calculated using the formula

ΔG = -nFE

where ΔG is the Gibbs free-energy change, n is the number of electrons transferred in the cell reaction, F is Faraday's constant (96,485 C/mol), and E is the cell potential.

For each AA battery, n = 1 and E = 1.50 V. Substituting these values into the formula, we get

ΔG = -1 × 96,485 C/mol × 1.50 V = -145,227 J/mol

Converting J/mol to kJ/mol, we get

ΔG = -145 kJ/mol

Therefore, the Gibbs free-energy change for the redox reaction in each of Luke's batteries is -145 kJ/mol.

Luke Skywalker Found That the Batteries for His Lightsaber Were