Question

1. suppose a substance expands (increases in volume) when it is cooled. is this a physical or chemical change? why?

Explanation:

A physical change involves a change in physical properties like shape, size, or state without altering the chemical composition. When a substance expands on cooling, its chemical composition remains the same. Only its physical property (volume) is changing.

Answer:

It is a physical change because the chemical composition of the substance does not change; only its volume (a physical property) is affected.