"We learned how most of these equations work through dating analogies. Synthesis is like when two single people get together to form one couple. Decomposition is like when a couple breaks up into single people. Single replacement is like when a someone leaves their boy/girlfriend for someone else. Double replacement is like when you have two couples and the women switch boyfriends. Combustion is the only one where we didn't learn an analogy. With combustion a hydrocarbon and oxygen combine to make water and carbon dioxide."