Question
GeneralGeneralGeneral

what is meant by a substance

Verified Answer

A substance is a pure form of matter that has a fixed composition and definite properties. It is made up of only one type of particles and cannot be separated into other kinds of matter by physical methods.

Substances can be:

  • Elements – made of one kind of atom
    Example: Iron (Fe), Oxygen (O2)

  • Compounds – formed when two or more elements combine chemically in a fixed ratio
    Example: Water (H2O), Carbon dioxide (CO2)

Characteristics of a substance

  • Has uniform composition throughout

  • Possesses definite physical and chemical properties

  • Cannot be separated by simple physical processes

For example, pure water is a substance because it always contains hydrogen and oxygen in the fixed ratio 2:1.

In chemistry, substances are different from mixtures because mixtures do not have fixed composition or uniform properties.