The amount of energy involved is usually smaller than the amount of energy involved in synthesis or decomposition reactions.

The difference between a double replacement and a single replacement reaction because the single replacement's free elememt is exchanged for another to yield a compound. A double replacement has components of 2 compounds that are exchanged to yield 2 new compounds.

It is different from combustion because nothing is being burned off from the compounds.

How can single replacement reaction be distinguished from other reactions?