Where does the energy given off by an exothermic reaction come from?

a. the chemicals make the energy during the reaction from atoms that are consumed.

b. the atoms in the air are converted to energy during the explosion.

c. the energy is converted from the heat taken in by the exothermic reaction.

d. more energy is given off by the new bonds formed than is needed to break the original bonds.

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.