A space capsule built with Aluminum alloy descends to earth surface from outer space (3 K, 13.22 Pa). After reaching into the stratosphere, the reentry capsule interacts with air molecules and generates lot of heat, often the surface temperatures go beyond 1500C at atmospheric pressure before landing into ocean.

a)Consider enthalpy and entropy as a function of (T, P) and develop the expressions for dH and dS that consists of Cp, , V, T, dT and dP.

b) Find H and S considering final state as T2 = Tavg = 780C, P2 = 101325 Pa & initial state as T1 = 3 K, P1 = 13.22 Pa.

c) Comment on the effect of pressure on H and S.