AFOQT Practice Test

In the context of chemistry, what happens during a physical change?

1. The chemical composition of substances changes

2. Only the state of matter changes

3. The identity of the substance changes completely

4. The temperature of the substances may change

The correct answer is: Only the state of matter changes

During a physical change, only the state of matter changes while the chemical composition remains the same. This means that the same substance is present before and after the change, regardless of whether it’s in a solid, liquid, or gas state. For instance, when ice melts to form water, the molecular structure of water does not change; only the arrangement and energy of the molecules alter, resulting in a different state. While temperature changes may occur during a physical change, they do not define such changes themselves. Similarly, a physical change does not involve a complete change in identity or composition of the substance, which aligns with the core definition of what a physical change entails.