What term describes something that is either an element or a compound?

• A. Pure substance
• B. Mixture
• C. Colloid
• D. Solution

Answer: (A)

A pure substance has a definite composition and can be either an element or a compound. Elements are made of a single type of atom, like oxygen or carbon. Compounds are chemical combinations of two or more elements bonded together, like water or sodium chloride. This fixed, specific composition is what defines a pure substance, exactly matching the idea of something that is either an element or a compound.

Mixtures are made from two or more substances physically combined, so their proportions can vary. Colloids are a type of mixture with larger particles dispersed throughout another substance, like milk. Solutions are homogeneous mixtures where substances are uniformly distributed at the molecular level, such as salt water. These are not pure substances because they involve more than one substance in the mixture.