Here's why:
* Mixtures are not chemically combined. The substances in a mixture retain their individual properties. This means the atoms of each substance remain independent.
* Variable proportions. The components of a mixture can be combined in any proportion. For example, you can make salt water with a lot of salt or a little salt. The ratio of water molecules to salt molecules can change.
Contrast with Compounds:
In contrast, a compound is formed when two or more elements chemically combine in a fixed ratio. For example, water (H₂O) always has a 2:1 ratio of hydrogen atoms to oxygen atoms. This fixed ratio defines the compound and gives it its unique properties.
Example:
* Mixture: Sand and water. You can have a lot of sand and a little water, or vice versa. The ratio of sand particles to water molecules is not fixed.
* Compound: Salt (NaCl). Sodium chloride always has one sodium atom for every chlorine atom, no matter how much salt you have.
