nh4no3, whose heat of solution is 25.7kj/mol, is one substance that can be used in cold pack. if the goal is to decrease the temperature from 25.0 c to 5.0 c, how many grams of nh4no3 should we use for every 100.0 g of water in the cold pack? assume no heat was lost outside of cold pack, and the specific heat of the resulted solution was the same as water