A gas originally at `1.10atm` and `298K` underwent a reversible adiabatic expansion to `1.00atm` and `287K`. What is the molar heat capacity of the gas?

Explanation

For reversible adiabatic expansion, in terms of pressure and temperature
`((T_(2))/(T_(1)))^(C_(P)//R) = (P_(2))/(P_(1))`
`((287)/(298))^(C_(P)//R) = ((1.00)/(1.10))`
`(C_(P))/(2) log((287)/(298)) = "log"(100)/(110)`
`-(C_(P))/(2) xx 0.01633 =- 0.04139 :. C_(P) = 5 cal mol^(-1)`