Final answer:
The change from liquid water to water vapor is a physical change, not a chemical change.
Step-by-step explanation:
Water changing from liquid to water vapor is actually a physical change rather than a chemical change. In a physical change, the substance undergoes a change in state or appearance, but its composition remains the same. When liquid water evaporates and turns into water vapor, no new substances are formed and the chemical composition of water remains the same - H₂O.
An example of a chemical change would be the burning of gasoline, where new substances are formed.
So, your friend is mistaken in claiming that the change from liquid water to water vapor is a chemical change.