Question

question 1
which of the following is a physical change?
oxidation of iron
water boiling into water vapor
fireworks
decomposition of nitrogen dioxide

Explanation:

A physical change is a change in which the substance changes form but not its chemical composition. Oxidation of iron is a chemical reaction forming iron - oxide. Fireworks involve chemical reactions for light and sound production. Decomposition of nitrogen dioxide is a chemical change. Water boiling into water vapor is a phase change from liquid to gas without changing the chemical nature of water (it's still H₂O).

Answer:

Water boiling into water vapor