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One mole of an ideal gas initially at 25C and 1atm is allowed to expand against an external pressure of 1atm until the final temperature is 400C. Assume that the gas has a constant specific heat of cv=20.8Jmol1K1. Determine (A) the work done by the gas during the expansion process, (B) the change in internal energy and the change in enthalpy of the gas during the expansion process, (C) the amount of heat absorbed by the gas during the expansion process, and (D) the change in entropy of the gas. (Ans: A= 3.12kJ)