Natural gas is a fuel that is used for heating and cooking in many homes and buildings. It is composed of almost pure methane, CH₄, and burns with a hot, blue flame. The chemical equation for the burning of methane is show below : CH4 + 2O2 → CO2 + 2H2O

Describe the burning of methane as a chemical reaction by explaining the following :

1. How can you tell from the chemical equation that this is a chemical reaction and not just a physical change ?

2.What observations would you see that indicate a chemical reaction?

3.is it an exothermic or endothermic reaction? What observation support your choice ?