Question

What are differences and similarities between a pure substance and a homogeneous mixture?

Answer 1

Pure substances are composed of a single element or compound while homogeneous mixtures are composed of multiple different elements or compounds.

Explanation:

A pure substance is composed of a single element or compound. Some examples of a pure substance are:
salt (NaCl), copper (Cu), and atmospheric oxygen (`O_2`)

A homogeneous mixture (also known as a solution) is composed of multiple pure substances in a uniform composition. Some examples are:
air (`N_2`, `O_2`, `CO_2`, etc), salt water (NaCl and `H_2O`) and brass (Cu and Zn)