1. Fill in the best answer for each of the following: a) ________________________ is the capacity to do work or to supply heat. b) ________________________ is energy stored within a substance due to its chemical composition. c) A reaction that absorbs energy is called a(n) ________________________ reaction. d) The __________________________________ says that in any chemical or physical change, energy can neither be created nor destroyed, only changed in form. e) Thermochemistry is the study of ________________________ that occur during chemical and physical changes.