Question

A piston filled with 0.04 mole of an ideal gas expand reversibly from 50.0mL to 375 mL at a consumed temperature of ${37.0}^{\circ }C$. As it does so, it absorbs ${208}^{\circ }C$ heat. The values of q and W for the process will be
(R = 8.314J/mol K, In 7.5 = 2.01)

• A. q = + 208J, W =-208
• B. q = -208J, W = -208
• C. q = -208, W = +208
• D. q = +208J, W =+208J

Answer 1

The correct option is A q = + 208J, W =-208

The process is isothermal expansion, hence
q = -W
$\Delta E=0$
$W=-2.303nRTlog\frac{V_2}{V_1}$
$=-2.303\times 0.04\times 8.314\times 310\times log\frac{335}{50}$
= -208J
q =+208, W = -208 (expansion work)