3) Cooling a Gas Mixture. It is required to cool a gas mixture composed of 75mol%N2,15 mol\% CO2 and 10mol%O2 from 800C to 350C. Determine the cooling duty of the heat exchanger in J/mol if the heat capacity expressions are in the form Cp(J/mol.K)=a+bT+cT2+dT3T[=]K where the coefficients a,b,c, and d are given by