A solvent is a molecule that can dissolve other molecules, known as solutes. A solvent can be solid, liquid or gas. 

A solvent’s molecules pull apart the solute’s molecules, and eventually the solute’s molecules become evenly distributed throughout the solvent. This homogeneous mixture cannot be separated physically. 

That means heat or another chemical process must be applied to the solution in order to separate the solvent from the solute. 

Popular solvents include water and organic compounds like benzene, tetrachloroethylene and turpentine.