I am having trouble understanding what exactly happens in an exothermic reaction. Specifically, I need to answer the following question: In an exothermic reaction: a) the kinetic energy increases and the potential energy decreases. b) the kinetic energy and the potential energy decrease. But I also would like to clarify my understanding of the subject. The way I understand it (which is probably flawed) is that the answer should be a). In an exothermic reaction, potential energy (from bonds) is converted into kinetic energy/heat that is released. Assuming an open system, does this heat go immediately into the surroundings, or does it have to be applied to the product first (thereby raising the temperature of the product, then by conduction the temperature of the surroundings)? If it does go immediately into the surroundings, how would this be possible? In either case, my reasoning is that a) would be the correct answer. If the potential energy is converted into heat that is applied to the product itself, then the kinetic energy would increase. If it is released directly into the environment, the kinetic energy would not directly be changed, but by conduction, kinetic energy would be transferred from the surroundings back into the product. And if it were a closed system, would the work just be applied to the product, in which case its kinetic energy would increase? Please help me understand, and correct me!