What are heterogeneous mixtures?

Heterogeneous mixtures are characterized by non-uniform composition and properties, meaning that the different components of the mixture can be visually distinguished and are not uniformly distributed throughout the mixture. This can include examples such as a salad, where you can see and separate the individual ingredients, or a mixture of sand and salt, where each substance retains its individual properties. The distinct regions or phases in heterogeneous mixtures highlight the variation in composition, making it easy to identify different components.

In contrast to heterogeneous mixtures, homogeneous mixtures have a uniform composition throughout, making it impossible to distinguish the individual substances within the mixture. Additionally, the term "substances that cannot be separated physically" refers more to pure substances or compounds, rather than mixtures. Lastly, the definition of mixtures in terms of solid states does not accurately capture the essence of what makes a mixture heterogeneous, as they can exist in multiple states (solid, liquid, gas) and still exhibit non-uniformity.