An ideal gas, Cp = (7/2)R, is heated in a steady-flow heat exchanger from 70°C to 190°C by another stream of the same ideal gas which enters at 320°C. The flow rates of the two streams are the same, and heat losses from the exchanger are negligible.
Calculate the molar entropy changes of the two gas streams for both parallel and countercurrent flow in the exchanger.
What is Stotal in each case?