Condensation+Reaction

According to the IUPAC Gold Book website, a condensation reaction is, "A (usually stepwise) reaction in which two or more reactants (or remote reactive sites within the same molecular entity) yield a single main product with accompanying formation of water or of some other small molecule, e.g. ammonia, ethanol, acetic acid, hydrogen sulfide."

To put it simply, a condensation reaction is a reaction in which two molecules chemically react to form water and another molecule. The H 2 0 forms as a result of the remainder of the other reactants needing a place to connect. The below example illustrates this: the H 2 0 is highlighted in blue. Should you look closely, you will notice where the C bonded with the OH group in molecule 1 and where the N bonded with H in molecule 2. On the reactants side, the C and N left behind by the H 2 0 are now bonded to form the new molecule, with a water molecule floating nearby. In a condensation reaction, the idea is that the molecules are condensing when they go from two molecules and join together to make one + water, which means it is then intermolecular. For example, a gas condensing into a liquid. Another common example is the condensation of amino acids to form one protein. (shown below)

This reaction is also used in things such as:
 * The formation of sugar
 * The formation of an Ester functional group
 * The formation of an Amide functional group
 * Making proteins from amino acids
 * Making synthetic materials

For more information see these pages. They were very helpful in writing this page.
 * [|Wikipedia Page on Condensation Reactions]
 * [|IUPAC Gold Book Page on Condensation Reactions]