Chemical a and chemical b react in an exothermic reaction. what can be known about what will happen when chemical a and chemical b are mixed together? a. the new substance will need more energy to form its chemical bonds than the old substance will release. b. more energy will be released from the old substance than the new substance will need to form its chemical bonds. c. the color will change as a result of the reaction. d. the substance will bubble as a result of the reaction.