A chemical substance is a form of matter that has constant chemical composition and characteristic properties.
Diamond is an example of a pure substance. Salexmccoy, Wikipedia Commons. Definition: A pure substance is a sample of matter with both definite and constant composition with distinct chemical properties. Alternate Spellings: chemical substance. Examples: water, diamond, gold, table salt (sodium chloride), ethanol.  In chemistry, matter is defined as anything that has rest mass and volume (it takes up space) and is made up of particles. The particles that make up matter have rest mass as well-not all particles have rest mass, such as the photon. Matter can be a pure chemical substance or a mixture of substances.  A chemical substance (also called a pure substance) may well be defined as any material with a definite chemical composition in an introductory general chemistry textbook. According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound. But, there are exceptions to this definition; a pure substance can also be defined as a form of matter that has both definite composition and distinct properties. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. A substance is matter which has a specific composition and specific properties. Every pure element is a substance. Every pure compound is a substance. Examples of substances: Iron is an element and hence is also a substance. Methane is a compound and hence is also a substance. Examples of non-substances: Salt water is not a substance. It is a mixture of two substances-sodium chloride and water. Its composition and therefore its properties are not fixed. Gasoline is not a substance. Substance. Definition. noun, plural:substances. (1) The physical matter, material or that of which an organ or body consists. (2) (chemistry) A material, matter or that which has definite chemical composition and distinct properties. (3) The most vital or essential part of something. (4) Drugs, as in substance abuse Chemical substances are any materials (in any state-solid, liquid or gas) that have a definite chemical composition. Chemical substances can therefore be either a pure chemical element or a pure chemical compound. : Chemical substances are any materials (in any state-solid, liquid or gas) that have a definite chemical composition. Chemical substances can therefore be. a pure chemical element. a pure chemical compound. This definition and interpretation is generally considered sufficient for school-level, incl GCSE Chemistry. There are, however, some other definitions e.g.  A form of matter that has both definite composition and distinct properties In addition to  element ,  mixture  and  compound , another useful term is the word  substance , which can be used to refer to either an element or a compound-but not to a mixture because a substance always has a definite composition. : Chemical substances are any materials (in any state-solid, liquid or gas) that have a definite chemical composition. Chemical substances can therefore be. a pure chemical element. a pure chemical compound. This definition and interpretation is generally considered sufficient for school-level, incl GCSE Chemistry. There are, however, some other definitions e.g.  A form of matter that has both definite composition and distinct properties A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory.
http://chemistry.about.com/od/chemistryglossary/g/Pure-Substance-Definition.htm https://en.wikipedia.org/wiki/Chemistry https://en.wikipedia.org/wiki/Chemical_substance http://www.chemicool.com/definition/substance.html http://www.biology-online.org/dictionary/Substance http://www.ivyroses.com/Chemistry/GCSE/What-is-a-substance.php http://www.ivyroses.com/Chemistry/GCSE/What-is-a-substance.php https://en.wikipedia.org/wiki/Chemical_substance
what is the definition of a substance in chemistry