What is a chemical property?

• A. Property indicating how much of a substance is present.
• B. Property that describes color and odor only.
• C. A characteristic that describes a substance's ability to undergo a chemical change (e.g., reactivity).
• D. Property that remains constant regardless of reaction.

Answer: (C)

A chemical property is about how a substance behaves in a chemical change—its tendency to react and form new substances. This is different from physical properties, which describe attributes you can observe without changing what the substance is, like color, odor, melting point, or density. The idea behind the correct choice is that it names a characteristic that describes the substance’s ability to undergo a chemical change, such as reactivity with oxygen, acids, or water, or flammability. For example, iron rusting in air shows a chemical property because it reveals how iron can chemically react to form a new substance. The other statements describe aspects that are not about chemical behavior: amount present is a quantity, not a chemical property; color and odor are typically physical properties observed without changing the substance; and claiming a property remains constant regardless of reaction misunderstands what a chemical property measures.