Which of the following is a characteristic of a compound?

A characteristic of a compound is that it is classified as a pure substance. Compounds have a definite and fixed composition, which means they are made up of two or more elements that are chemically bonded together in specific ratios. This bonding results in the formation of a new substance with unique properties that differ from the individual elements.

For example, water (H2O) is a compound made of two hydrogen atoms and one oxygen atom. This compound exhibits unique characteristics and behaviors that are not found in either hydrogen or oxygen alone. The nature of compounds also means that they cannot be separated into their constituent elements through physical means; such separations require chemical reactions instead.

This is why compounds are distinct from mixtures, which can vary in composition and can be separated by physical processes.