A solution is a homogeneous mixture of two or more substances. The solute is the substance that is dissolved in the solvent. The solvent is the substance that does the dissolving. In an ordinary mixture, the components are not uniformly distributed throughout the mixture. For example, if you mix sand and water, the sand will settle to the bottom of the container. However, if you dissolve salt in water, the salt will be evenly distributed throughout the water.

Another key difference between a solution and an ordinary mixture is that the components of a solution cannot be separated by physical means. For example, if you mix sand and water, you can use a filter to separate the sand from the water. However, if you dissolve salt in water, you cannot use a filter to separate the salt from the water. You would need to use a chemical process, such as distillation, to separate the salt from the water.