The change in entropy accompanying the heating of one mole of helium gas (), assumed ideal, from a t — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

$\Delta S = n C_P \ln\left(\frac{T_2}{T_1}\right)$. $C_P = C_V + R = \frac{5R}{2}$. $\Delta S = 1 \times \frac{5R}{2} \ln\left(\frac{1000}{250}\right) = 2.5R \ln 4 = 5R \ln 2$. Using $R \approx 2 \text{ cal/mol-K}$, $\Delta S = 5(2)(0.7) = 7.0 \text{ cal/K}$.