Solvent

Separation methods use physical differences between the substances, such as whether they dissolve, their boiling points, or how they move with a solvent. No new substances are made. Before choosing a method, decide what is mixed and which substance you want to collect.

When a solute dissolves in a solvent, it forms a solution. For example, sodium chloride dissolves in water to form an aqueous solution. Concentration tells you how much solute is present in a given volume of that solution.

For example, salt dissolves in water to make a solution: salt is the solute and water is the solvent. Sand does not dissolve in water.

In paper chromatography, a solvent moves up the paper and carries dissolved substances with it. The paper is the stationary phase and the solvent is the mobile phase. A substance's movement depends on how it distributes itself between these two phases.