3) Cooling a Gas Mixture. It is required to cool a gas mixture composed of 75 mol% N2, 15 mol% CO2 and 10 mol% O2 from 800 C to 350 C. 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 +cT + dT T [=] K where the coefficients a, b, c, and d are given by Species a N 28.882 bx 102 - 0.1570 CX 105 0.8075 d x 109 2.8706 02 25.460 1.5192 -0.7150 1.3108 CO2 21.489 5.9768 - 3.4987 7.4643