Contrast a mixture and a pure substance. In your answer be sure to explain what each is, how you can tell them apart, and supply an example for each.

A pure substance has a definite and constant composition. A pure substance can be either an element or a compound, but the composition of a pure substance doesn’t vary. Ex: salt or sugar

Mixtures are physical combinations of pure substances that have no definite or constant composition - the composition of a mixture varies according to who prepares the mixture. Ex: sand mixed with salt