Year 7 Chemistry

Chemical Mixtures

Chemical  mixtures  contain two or more distinct chemical components in either a heterogeneous or homogeneous state. They do not have a constant chemical composition and cannot be represented by a chemical formula. The substances in a mixture, regardless of how thoroughly they are mixed, do not react with each other chemically. A heterogeneous mixture consists of substances that have distinct and different phases, such as ice cubes and  water. Homogenous mixtures, in contrast, consists of substances in a single phase, as in a mixture of  gases.

Solutions and Mixtures. (2000). In World of Chemistry. Detroit, MI: Gale. Retrieved from

Additional Resources

Chemical Changes

Categories of Mixtures

There are two main categories of mixtures: homogeneous mixtures and heterogeneous mixtures. In a homogenous mixture all the substances are evenly distributed throughout the mixture (salt water, air, blood). In a heterogeneous mixture the substances are not evenly distributed (chocolate chip cookies, pizza, rocks).

Ducksters Education Site. (n.d.). Chemistry for Kids: Chemical Mixtures. Retrieved from


What do students need to know about mixtures and solutions?

  • Mixtures are materials that contain two or more chemical substances dispersed among each other (mixed together).
  • If no chemical reaction occurs when two materials are mixed, they form a mixture. The chemical properties of the components don’t change.
  • Mixtures can be separated by physical methods.
  • There are two general types of mixtures: homogeneous and heterogeneous.
  • Homogeneous mixtures: the particles of the substances are mixed together (there is no clumping of the particles) – eg air.
  • Solutions are homogenous mixtures: particles of one substance (the solute) are mixed together with the particles of another substance (the solvent) – eg salty water.
  • Heterogeneous mixtures: large aggregations (clumps) of the substances are mixed together – eg emulsions like oil in water.

Paterson, D. (2018). How to Teach Mixtures and Solutions. Retrieved from

Chemistry for Dummies