Pure Substance

Definition

A pure substance is a form of matter that has a constant composition and properties that are consistent throughout the sample. It cannot be separated into different types of matter by physical means.

Related terms

Element:

A type of pure substance which cannot be broken down into simpler substances by ordinary chemical methods.

Compound:

Another type of pure substance composed of two or more elements in fixed proportions.

Homogeneous Mixture:

A mixture (not a pure substance) that has uniform composition and properties throughout.