The following liquids, all at atmospheric pressure and 300 K, are mixed: 25 kg of pure water, 40 kg of pure sulfuric acid, and 75 kg of 25-wt-% sulfuric acid.
(a) How much heat is liberated if mixing is isothermal at 300 K?
(b) The mixing process is carried out in two steps: First, the pure sulfuric acid and the 25-wt-% solution are mixed, and the total heat of part (a) is extracted; second, the pure water is added adiabatically. What is the temperature of the intermediate solution formed in the first step?