Question

Chemical reactions either release or store energy. In endothermic reactions, energy is stored as heat, and you might notice a decrease in temperature. In exothermic reactions, heat energy is released, and temperature will increase. Chemical reactions store or release chemical energy, too. Chemical energy is stored in chemical bonds, and when bonds break, that energy is released.

According to the passage, what evidence can show if a reaction is endothermic or exothermic?


a. the presence of bubbles

b. a temperature change

c. glass breaking

d. none of the above

Answer 1

Step-by-step explanation:

The passage is all about temperature. Remember that it is an external piece of evidence.

When you say that a reaction is exothermic, what you are really saying is that when the bonds break, the energy created must be given away.

When you say the reaction of endothermic what you are saying is that the bonds will break only if the reaction can get heat from the environment and thus make the environment feel cooler.

The answer is therefore, B