What Is A Pure Substance In Chemistry?

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A pure substance is defined as a form of matter with constant composition and constant properties throughout the sample.  

When we talk about a pure substance, we are talking about something that includes only one kind of matter. This can be either one single compound or one single element. And every sample of a pure substance you examine may consist of precisely the same thing with a definite and fixed set of properties. 

Pure substances are classified as compounds and elements

Compounds are pure substances when two or more elements are combined chemically in a fixed ratio. However, which can be broken down into separate elements by chemical methods.

An element, on the other hand, is a substance that comprises only one kind of atom. An element is a pure substance that cannot be broken down into a new substance, not even through chemical or physical means. 

For instance, let us take a look at a few pure substances:

Water (H2O): Element: Consists of water molecules

Ammonia (NH3): Compound: Consist of ammonia molecules

Lead (Pb): Element: Consists of lead atoms

Properties and Characteristics of Pure Substances!

Pure substances are homogeneous in nature, which means containing only one type of molecule or atom.
Pure substances have a uniform or constant composition throughout. 
Pure substances have fixed melting and boiling points.
Pure substances participate in the chemical reaction to produce predictable products.