if the gas is air with a fixed mass m of 1 kg, a pressure p of 20 atm, and a temperature t of 600 k; calculate the work done by expanding the gas in the cylinder to a pressure of 1 atm. assume the expansion to be reversible and adiabatic. perform the calculation directly by integrating compare this value of work to the change in internal energy of the gas and to the change in enthalpy of the gas. comment. if the temperature is raised to 1200 k before the expansion begins, determine the work of expansion if the initial pressure is unchanged. compare this result to the result from part a. repeat the calculations in parts a-c using argon as the working fluid. explain what gas property leads to a different result.