Chapter 12, Problem 52P

A sealed container holding 0.500 kg of liquid nitrogen at its boiling point of 77.3 K is placed in a large room at 21.0°C. Energy is transferred from the room to the nitrogen as the liquid nitrogen boils into a gas and then warms to the room’s temperature. (a) Assuming the room’s temperature remains essentially unchanged at 21.0°C, calculate the energy transferred from the room to the nitrogen. (b) Estimate the change in entropy of the room. Liquid nitrogen has a latent heat of vaporization of 2.01 × 10⁵ J/kg. The specific heat of N₂ gas at constant pressure is $C_{{\text{N}}_2}$ = 1.04 × 10³J/kg · K.