Question: What is the change in entropy when 1 mole of an ideal gas expands isothermally and reversibly from volume V1 to V2?
Options:
Correct Answer: R ln(V2/V1)
Solution:
The change in entropy for an isothermal and reversible expansion of an ideal gas is given by ΔS = nR ln(V2/V1). For 1 mole, n = 1, hence ΔS = R ln(V2/V1).