For a reversible isothermal expansion of an ideal gas, the change in entropy is given by
Q1. For a reversible isothermal expansion of an ideal gas, the change in entropy is given by
Answer: nR ln(V_f / V_i)
Explanation: ΔS = Q / T = nRT ln(V_f / V_i) / T = nR ln(V_f / V_i). Other options misapply the formula for entropy change.