A chemical substance is any material with a known chemical composition. For example, water has the same properties and the same ratio of hydrogen to oxygen whether it came from a river or was made in a laboratory. Typical chemical substances found in the home include water, salt (sodium chloride) and bleach. Generally, substances exist as a solid, a liquid, or a gas, and may change between these phases of matter when there are changes in temperature or pressure.
- Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., p5, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.