Instant cold packs are used for first aid when ice is not available. In one such device, a small pouch containing 2.00 × 102 grams of ammonium nitrate (NH4NO3) is placed in a bag containing 2.00 × 102 milliliters of water initially at 25°C. When the pouch is broken, the ammonium nitrate dissolves in the water and the cold pack reaches a final temperature of - 2°C.
(a) Calculate ΔHs for the solution in the cold pack, assuming that the pack loses a negligible amount of heat to the surroundings during the dissolution process and that the heat capacity of the solution is that of pure water.
(b) What would be the final temperature of a pack containing 300 grams of ammonium nitrate and 300mL of water?