Final answer:
A chemical mixture occurs when two or more substances are combined without chemical bonding, retaining their own properties, and can be either heterogeneous or homogeneous.
Step-by-step explanation:
The best description of a chemical mixture is when two substances are combined, but are not chemically bonded. A mixture is a combination of two or more substances where these substances do not undergo a chemical reaction to bond together and each part in the mixture retains its own properties. Unlike a compound, a mixture does not have a fixed composition.
Examples of mixtures include sand and salt mixed together, air (which is a mixture of various gases), and oil mixed with water. Mixtures can be either heterogeneous or homogeneous. A heterogeneous mixture has a non-uniform composition, whereas a homogeneous mixture has a consistent composition throughout.