A45.0%/55.0% by volume propane/n-butane mixture is cooled from 315 degree c to 165 degree c. find the change in enthalpy of this mixture by following the steps below. assume ideal behavior. a) what is the average molar mass of the mixture? b) what is the change in specific enthalpy of pure propane from 315 degree c to 165 degree c? c) what is the change in specific enthalpy of pure n-butane from 315 degree c to 165 degree c? d) what is the change in specific enthalpy of the mixture from 315 degree c to 165 degree c? e) what is the change in enthalpy of the mixture from 315 degree c to 165 degree c in kj/kg?