A mixture is a combination of two or more substances that are not chemically combined. The individual substances in a mixture retain their original properties, and the mixture itself can be separated into its components by physical means. Examples of mixtures include air, soil, and salt water.
A compound is a combination of two or more elements that are chemically combined. This means that the individual elements in a compound have lost their original properties and have become something new. Compounds cannot be separated into their components by physical means; they must be broken down chemically. Examples of compounds include water, table salt, and sugar.