Middle School Physical Science: Chemistry of Solutions - Introduction to Solutions — Flashcards

A solution is a homogeneous mixture of two or more pure substances. The substance that is in a large amount in the solution is called the solvent. The substance that is in smaller amounts in a solution is called the solute.

Solutes and Solvents    
A solution forms when one substance dissolves in another. The substance that dissolves is called the solute. The substance it dissolves in is called the solvent.

For example, ocean water is a solution in which the solute is salt and the solvent is water. In this example, a solid (salt) is dissolved in a liquid (water). However, matter in any state can be the solute or solvent in a solution.    
When a solute dissolves in a solvent, it changes to the same state as the solvent. For example, when solid salt dissolves in liquid water, it becomes part of the liquid solution, salt water. If the solute and solvent are already in the same state, the substance present in greater quantity is considered to be the solvent.

For example, nitrogen is the solvent in Earth's atmosphere because it makes up 78 percent of air.