Oxygen gas weighing 64 g is expanded from 1 atm to 0.25 atm at . What is the entropy change, assumin — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

Moles of $\text{O}_2 = 64\text{ g} / 32\text{ g/mol} = 2\text{ mol}$. For isothermal expansion, $\Delta S = n R \ln(P_1/P_2) = 2 \times 8.3 \times \ln(1/0.25) = 16.6 \times \ln(4) = 16.6 \times 1.4 = 23.24\text{ J/K}$.