What are chemical reactions?
Found two definitions: #1noun: (chemistry) a process in which one or more substances are changed into others; “there was a chemical reaction of the lime with the ground water” . WordNet® 2.1, © 2005 Princeton University #2: A process in which atoms of the same or different elements rearrange themselves to form a new substance. While they do so, they either absorb heat or give it off. [Chapter:] Physical Sciences and Mathematics WordNet® 2.