coletted

Hi, I'm new to this site and was wondering if anyone can help me on an assignment. My assignment is about food heating packs. What happens to the surroundings in an exothermic heat pack, its energy changes, the chemicals in the heat packs the bonding breaking and making, oh and the word equations. I can't seem to find any of these things to research on the internet. So I'm hoping there's someone on here that can help me, because I'm at desperate point now. Thanks for reading xx