In chemistry, a solution's a homogeneous mixture composed of two or more substances. In such a mixture, a solute's dissolved in another substance, known as a solvent. Gases may dissolve in liquids, for example, carbon dioxide or oxygen in water. Liquids may dissolve in other liquids. Gases can combine with other gases to form mixtures, rather than solutions. All solutions are characterized by interactions between the solvent phase and solute molecules or ions that result in a net decrease in fr… (More on Solute)