A 50/50 (by mass) gas mixture of methane CH4 and ethylene C2H4 is contained in a cylinder/piston

Question:

A 50/50 (by mass) gas mixture of methane CH4 and ethylene C2H4 is contained in a cylinder/piston at the initial state 480 kPa, 330 K, 1.05 m3. The piston is now moved, compressing the mixture in a reversible, polytropic process to the final state 260 K, 0.03 m3. Calculate the final pressure, the polytropic exponent, the work and heat transfer and entropy change for the mixture.