PLS HELP I WILL VOTE THE PERSON WHO HELPS ME WITH THIS BRAINLEST

Answer:
1. One molecule of methane, (the [g] referred to above means it is gaseous form), combined with two oxygen molecules, react to form a carbon dioxide molecule, and two water molecules usually given off as steam or water vapor during the reaction and energy. Natural gas is the cleanest burning fossil fuel.
2.a. Propane
2.a.