Given the balanced equation representing the reaction between methane and oxygen:

CH4+2O2 - - >CO2+2H20

According to this equation, what is the mole ratio of oxygen to methane?

The correct answer is 2 moles of oxygen to 1 mole of methane.

The number of moles will correspond to the number in front of each molecule in the equation. Since there is a 2 in front of oxygen, the moles of oxygen is 2, and since there is no number in front of methane (CH4), we can deduce that there is 1 mole of methane.