Which describes a heterogeneous mixture?

• A. It has a uniform composition throughout
• B. It has non-uniform distribution of components
• C. It is a pure substance
• D. It forms a solution

Answer: (B)

The difference here is that a heterogeneous mixture has parts that aren’t evenly mixed, so the distribution of components varies from one region to another. That non-uniform distribution is exactly what describes a heterogeneous mixture, because you can often spot different substances or phases in different spots. By contrast, uniform composition throughout points to a homogeneous mixture (or a true solution), a pure substance is a single material with fixed composition, and forming a solution is a type of homogeneous mixture where the components are evenly dissolved.