Which statement best characterizes a heterogeneous mixture?

• A. Mixtures (not uniformly mixed)
• B. Elements only
• C. Pure substances with fixed composition
• D. Compounds only

Answer: (A)

Heterogeneous mixtures have components that aren’t distributed evenly, so you can see different substances in different parts of the sample. That uneven distribution is what makes them stand out from substances that are uniform throughout.

So the statement that best characterizes a heterogeneous mixture is that mixtures are not uniformly mixed. In a single glance, you can often identify the distinct components or phases, like in a salad, granite, or soil where different materials sit side by side.

The other descriptions refer to substances with fixed, uniform composition. Elements are pure single types of atoms, not mixtures. Pure substances with fixed composition cover both elements and compounds that are uniform throughout. Compounds are chemically bonded combinations with fixed ratios, also uniform. None of these describe the variable, region-to-region composition that defines a heterogeneous mixture.