The standard reaction enthalpy for the decomposition of cacl2 · nh3(s) into cacl2(s) and nh3(g) is nearly constant at +78 kj mol−1 between 350.k and 470.k. the equilibrium pressure of nh3 in the presence of cacl2 · nh3 is 1.71 kp a at 400.k. find an expression for the temperature dependence of ∆rg◦ m in the same range.

Estimate the change in specific internal energy au and specific enthalpy h from inlet to outlet for ethylene glycol (a liquid) flowing through each of the following devices: (a) a heat exchanger where the glycol temperature increases from 20 °c to 80 °c; (b) a pump operating at about 25 °c and increasing the glycol pressure from 100 kpa to 8 mpa.