Mixtures, Heterogeneous, & Homogeneous
Mixture is a combination of two or more pure substances. Mixtures are classified as either heterogeneous or homogeneous. Homogeneous mixtures have constant composition throughout. They always have a single phase. Homogeneous also are referred to as solutions. Heterogeneous is one that doesn't blend easily throughout, individual substances remain distinct.
There are a couple common separation techniques which are distillation, filtration, crystallization, and chromatography. Most homogeneous mixtures are able to be separated by distillation. Solid objects in liquid can be separated by filtration. Those two techniques are the main ones people use to seperate mixtures.