What is the correct chemical equation for the reaction between methane and oxygen to produce carbon dioxide and water?

The answer to your question is:   CH₄     +    3/2 O₂     ⇒     CO₂    +   2 H₂O

Explanation:

Methane = CH₄

Oxygen = O

Carbon dioxide = CO₂

Water = H₂O

                      CH₄     +    3/2 O₂     ⇒     CO₂    +   2 H₂O

        This is the balanced equation

the volume of fluid displaced would equal the volume of the gas. use a gas syringe - this is a laboratory instrument that can be used to withdraw a certain volume of gas from a closed system or to measure the volume of gas from a chemical reaction.