Final answer:
A condensation reaction involves combining two molecules to form a single molecule and releases a small molecule like water. Addition reactions occur when an atom or molecule is added to an unsaturated molecule, typically containing double or triple bonds.
Step-by-step explanation:
A condensation reaction, also known as dehydration synthesis, is a reaction in which two molecules combine to form a single molecule, with the loss of a small molecule like water. This type of reaction forms organic molecules, such as peptides in the reaction between two amino acids. It involves the removal of an OH group from one molecule and an H group from another molecule to form a water molecule as a byproduct.
An addition reaction is a reaction in which an atom or molecule is added to an unsaturated molecule, resulting in a single product. Addition reactions are typically carried out by unsaturated organic molecules, such as alkenes or alkynes, due to the presence of double or triple bonds that allow for the addition of atoms or molecules.