ACS Chemistry Practice Exam 2026 – The All-in-One Guide to Exam Success!

The correct choice highlights a physical property, which refers to a characteristic of a substance that can be observed or measured without altering its chemical structure or identity. Physical properties include attributes such as color, boiling point, melting point, density, and state of matter (solid, liquid, gas). For instance, if you take a piece of ice and measure its temperature, you are observing a physical property (temperature) without changing the identity of the substance, which remains water.

In contrast, a chemical property describes how a substance interacts with other substances and involves a change in the substance’s chemical identity. For example, flammability or reactivity with acids are chemical properties because they involve chemical changes.

Intensive properties are those that do not depend on the amount of substance present, such as density or boiling point, while extensive properties do depend on the quantity, like mass and volume. Although both intensive and extensive properties fall under the broader category of physical properties, the key aspect of the question is to recognize that physical properties can be observed without changing the identity of the substance, making physical property the most appropriate answer.