I know this is a physics forum, but this problem is mainly physics, and exceedingly simple: 1. The problem statement, all variables and given/known data A certain reaction releases about 90 kJ of heat when stoichiometric amounts of reactants react. If the reaction goes to completion in 100 g of water whose initial temperature is 20 deg C, what is the final temperature of the water? 2. Relevant equations q = mc(delta T), I believe, so delta T = q / (mc) 3. The attempt at a solution I don't know what I'm doing wrong, but if I plug the 400 kJ = 400000 J into q and the 100 g mass into m and 4.184 J / (mol deg C) into c, I get an insane change in temperature around 215 degrees. I am obviously forgetting some step or misunderstanding something... I've always had trouble with thermodynamics stuff like this. Any help would be greatly appreciated.. thank you!