The three general types of mixtures in chemistry are solutions, suspensions and colloids. All mixtures contain at least two different substances and can be liquids, gases or solids.
Solutions are the simplest mixture, consisting of two substances that interact and have reasonably small particle sizes. A solution has a solvent and at least one solute, depending on how many substances are being mixed together. If any of the substances changes phase while making the solution, it is considered a solute. If there are no phase change between two or more substances, the substance that there is the most of is considered the solvent, while all the rest are solutes.
A suspension is a mixture where components must be forced to distribute evenly. In time, if left to rest, the components will separate into layers. A common example of this is oil and water, which needs to be shaken to ensure a temporarily uniform solution.
Colloids are mixtures where substances are evenly distributed, but not fully dissolved due to a large particle size. The substances with the largest particles can be filtered out through a membrane. To test for a colloid, a light is shone through the mixture. The light will simply shine through a true solution, but be clearly visible when shone on a colloid mixture.