Question

1. explain why the evaporation of water is a physical change and not a chemical change.

Explanation:

Physical change involves no new substance formation. Evaporation of water changes water from liquid to gas (water vapor), but the chemical composition ($H_2O$) remains the same. In a chemical change, new substances with different chemical properties are formed. Since evaporation of water doesn't create new substances, it's a physical change.

Answer:

The evaporation of water is a physical change because no new substances are formed. The water changes from liquid to gas (water vapor), but its chemical formula ($H_2O$) remains unchanged. In a chemical change, new substances with different chemical properties would be produced, which is not the case here.