A heterogeneous mixture is characterized by

• A. Uniform composition throughout
• B. Contains two or more phases with distinct regions
• C. Always a pure substance
• D. Can only be separated chemically

Answer: (B)

A heterogeneous mixture shows different parts that can be distinguished by appearance or properties. The components are not spread evenly, so you have two or more regions with distinct compositions or phases, like oil droplets in water, rock with mineral bands, or a salad with separate ingredients. This uneven distribution is what lets you separate the mixture by physical means, such as filtration or decanting, without changing the substances themselves.

The idea that a mixture has uniform composition throughout describes a homogeneous mixture, not a heterogeneous one. Saying it’s always a pure substance ignores the fact that a mixture by definition contains more than one substance. And claiming it can only be separated chemically is incorrect because heterogeneous mixtures can often be separated by physical methods based on differences in phase or properties.