You have been given the task of designing a heat pack to relieve soreness in muscles by combining oxygen and iron. The more oxygen that is added to iron, the more it will heat up. Which of the following temperature changes would you be looking for? A. There will not be a reaction
B. An increase in temperature, showing an endothermic reaction
C. You should not expect a temperature change because this is a physical reaction
D. An increase in temperature, showing an exothermic reaction

How is electrolysis most commonly used to produce an energy source? a - splitting water molecules produces oxygen, which organisms breathe to fuel their bodies. b - splitting water molecules produces hydrogen gas, which is used to power machines through hydrogen fuel cells. c - splitting carbon dioxide molecules produces coal, a form of carbon that can be burned to produce heat. d - splitting carbon dioxide molecules produces natural gas, which can be burned to generate electricity in power plants.