Question

One kilogram of fresh air is compressed isothermally and reversibly from
1.0 bar and 30 oC to 5.0 bar. Calculate the work done w on the air and
the heat flow q to or from the air.

Answer 1

$W=\frac{m}{M}RT\ln{\frac{p_1}{p_2}}=\frac{1}{0.029}\cdot 8.31\cdot 303\cdot\ln{\frac{100000}{500000}}=-140(kJ)$

$Q=\Delta U+W=0+W=-140(kJ)$