4.2.5 Journal: Reactions Around You List 10 chemical reactions that have benefited your life today. Include the reasons you think each was indeed a chemical reaction and not just a physical change. (20 points) Think about processes in your body, processes in the atmosphere, or chemical reactions that may be involved with any materials or products you have used.

the answer is d.) potassium

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.