Mixture: definition in chemistry
Mixture: Two or more substances physically combined, each keeping its own properties. Mixtures can usually be separated by physical means such as filtering, evaporation or distillation.
Unlike a compound, a mixture has no fixed composition: you can stir more salt into salt water and it is still salt water. Mixtures are either homogeneous (uniform throughout, also called solutions) or heterogeneous (visibly uneven). Most materials around us, from air to soil to food, are mixtures rather than pure substances.
Examples
- Air — nitrogen, oxygen, argon and other gases
- Salt water — salt dissolved in water
- Sand and iron filings, which can be separated with a magnet
- Trail mix — nuts, raisins and chocolate you can pick apart
On the periodic table
The periodic table lists pure elements, but in nature many of them are found as parts of mixtures, such as the nitrogen, oxygen and argon in air.