Question

a sample liquid is cooled from 150°c to 30°c, causing the liquid to change into a solid. which of the following has occurred? evaporation of a solvent has occurred. a physical change has occurred. chemical composition has changed. a new compound has formed.

Explanation:

• Evaporation involves liquid turning to gas, not solid, so this is incorrect.
• When a liquid cools and becomes a solid (freezing), it's a physical change as the substance's chemical identity remains the same, only the state (phase) changes.
• Chemical composition changing would be a chemical change, but here it's a phase change (physical), so this is incorrect.
• A new compound forming is a chemical change (new substance), but freezing is physical, so this is incorrect.

Answer:

The correct option is the one stating "A physical change has occurred." (Assuming the option is labeled, for example, if it's the second option: B. A physical change has occurred.)