Chemical reactions can yield more than one resultant compound as product. It is often necessary to separate these, one from the other. They may be similar in chemical composition, as in the case of stereoisomers. Separating even very similar products of a chemical reaction is what is meant by the expression “resolve a mixture of compounds.”

Mixtures of compounds can be separated in a number of ways. The method of choice depends upon the compound’s state. Liquids may be distilled. Precipitates may be removed by filtration. Organic compounds may be separated by a form of chromatography. Even a difference in densities can be used to separate compounds, whether by separatory funnel or by centrifuge. Historically, even nearly identical chemicals called enantiomers were separated by Louis Pasteur by hand.