Formation of a precipitate is usually evidence of?
the separation of a mixture, a chemical change, formation of a mixture, physical change

Formation of precipitate is usually an evidence of a chemical change. The precipitate is a new substance that gets created due a chemical reaction between two or more different substances.  The precipitate can be the formation of a solid within a liquid or the formation of a solid within a solid due to a chemical reaction or change. The solid formation within a liquid is known as precipitate. This kind of chemical reaction can be seen in normal and daily life, as well as in laboratories.