A cylinder with a movable piston holds 2.75 mol of argon gas at a constant

temperature of 295 K. As the gas is compressed isothermally, its pressure increases from
101 kPa to 121 kPa. Find (a) the final volume of the gas, (b) the work done by the gas,
and (c) the heat added to the gas.

1 answer

(a) PV = constant for an isothermal gas
(b) Work done = -Integral of P dV
= -integral of PoVo*dV/V
= PoVo*dP/P
= PoVo ln(P2/P1)

(c) Qin = Wout + deltaU
= Wout

The internal energy does not change for an ideal isothermal gas.