Module 10: Solutions

You come into contact with various solutions every day of your life. Before you started this module, you may have thought that solutions are liquids only; however, solutions can include solids, liquids, or gases. Adding a little salt or sugar to water creates a solution, but solutions can also be of solid form. Steel is a different mixture of carbon and iron atoms. Solutions can exist as gases, but only if the gases are dissolved under a set of conditions. The best example of a solution as a gas is the air which you breathe. In this example, all gases are dissolved in nitrogen. A solution is always composed of a solvent, or dissolving medium, and a solute, the substance being dissolved. Sometimes it is not easy to determine which substance in a mixture is the solvent. In that case, the substance which is present in the largest amount is considered to be the solvent. Mixtures can also be heterogeneous, which is a mixture with visible parts.