1.A pure substance is a form of matter that has a fixed chemical composition and a distinct characteristic while a homogeneous mixture is a mixture of two or more compounds with compositions that are uniform or mixed together in such a way that they are indistinguishable from each other.
2.A pure substance cannot be separated into two or more substances by any means while a homogeneous mixture can be separated into two or more substances through physical or mechanical processes such as distillation, filtration, or sifting.
3.While both a pure substance and a homogeneous mixture have uniform compositions throughout, it is impossible to extract the components of a pure substance while the pure substances that make up a homogeneous mixture can be extracted because they retain their properties even when mixed together.
4.The components of a homogeneous mixture melt or boil at different temperatures while the temperature when boiling or melting a pure substance does not change until all the pure substances have boiled or melted.