Thermodynamics and Thermochemistry - Result Question 101
####26. A piston filled with 0.04 mole of an ideal gas expands reversibly from $50.0 mL$ to $375 mL$ at a constant temperature of $37.0^{\circ} C$. As it does so, it absorbs $208 J$ of heat. The values of $q$ and $W$ for the process will be
$(R=8.314 J / mol K, \ln 7.5=2.01)$
(2013 Main)
(a) $q=+208 J, W=-208 J$
(b) $q=-208 J, W=-208 J$
(c) $q=-208 J, W=+208 J$
(d) $q=+208 J, W=+208 J$
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Solution:
- The process is isothermal expansion, hence
$$ \begin{aligned} q & =-W \ \Delta E & =0 \ W & =-2.303 n R T \log \frac{V _2}{V _1} \ & =-2.303 \times 0.04 \times 8.314 \times 310 \times \log \frac{335}{50} \ & =-208 J \ q & =+208 J \ W & =-208 J \quad \text { (expansion work) } \end{aligned} $$
