Question: What is the entropy change when 2 moles of an ideal gas are compressed isothermally from volume V2 to V1?
Options:
Correct Answer: -R ln(V1/V2)
Solution:
The change in entropy for an isothermal compression is ΔS = nR ln(V1/V2). For 2 moles, ΔS = 2R ln(V1/V2), which is negative since V1 < V2.