Heat capacity of air can be approximately expressed as, C_{p} = 26.693 + 7.365 x10^{-3}T, where, C_{p} is in J/mole.K and T is in K. The heat given off by 1 mole of air when cooled at atmospheric pressure from 500°C to - 100°C is

Equal masses of CH_{4} and H_{2} are mixed in an empty container. The partial pressure of hydrogen in this container expressed as the fraction of total pressure is