- Substances are made of molecules
- Gas is a kind of substance
- Therefore, a gas is made of its molecules

- A gas is made of its molecules
- A gas is heated and its temperature increases
- As the temperature of a substance increases , the molecules in that substance will move faster / farther apart
- Therefore, the molecules in the gas will move faster

Hence, the molecules in the gas will move faster
Question: A gas is heated and its temperature increases. What happens to the gas molecules?
Context: - Substances are made of molecules 
- A gas is heated and its temperature increases 
- As the temperature of a substance increases , the molecules in that substance will move faster / farther apart 
- Gas is a kind of substance