- The metal on the roof of a car is exposed to air
- If something is exposed to air, then that something is in contact with air
- So, the metal on the roof of a car is in contact with air

- The metal on the roof of a car is in contact with air
- Air contains oxygen and water vapor
- Hence, the metal on the roof of a car is in contact with oxygen and water vapor

- The metal on the roof of a car is in contact with oxygen and water vapor
- Metal in contact with water and oxygen will rust
- Hence, the metal on the roof of a car rusts

So, the metal on the roof of a car rusts
Q: Base your answer on the information below and on your knowledge of science. A baseball strikes the roof of a car and dents it. The paint on the roof begins to crack and chip, exposing the metal. The exposed metal on the roof rusts, eventually causing a small hole in the roof. Which event is a chemical change?
Context:
- Metal in contact with water and oxygen will rust 
- Air contains oxygen and water vapor 
- The metal on the roof of a car is exposed to air 
- If something is exposed to air, then that something is in contact with air