9) how do you know a chemical change has occurred? a. new bonds have formed or bonds have broken. b. the matter has had a change in state. c. the temperature has changed. d. all of the above e. only a and c are indicators of a chemical change. ! 15 pts 10) if a chemical bond is formed or destroyed, what changes? a. energy is absorbed or released. b. protons are absorbed. c. neutrons will vary. d. energy is destroyed. e. protons are released.