Which of the following describes a mixture?

A mixture is defined as a combination of two or more substances that are not chemically combined. This means that each substance in a mixture retains its individual properties and can be separated by physical means.

In a mixture, the components can often be present in varying proportions and do not undergo any chemical changes during the combination process. This is what distinguishes mixtures from compounds where the substances are chemically bonded together, resulting in new properties.

For instance, in a mixture of sand and salt, both substances retain their original characteristics and can be separated by dissolving the salt in water and filtering the sand. Mixtures can be either homogeneous, where the composition is uniform throughout (like air or a saltwater solution), or heterogeneous, where the components are distinctly separate (like a salad).

Other definitions inaccurately describe mixtures: a chemical bond implies a reaction and new substance formation; a single substance does not classify as a mixture; while a homogeneous solution represents just one specific type of mixture. Thus, the characterization of a mixture as two or more substances that are not chemically combined is the most accurate description.