Review this chemical equation: O2 + CH4---> CO2 + H2O Which answer best explains what must be done to make this equation comply with the law of conservation of mass?

To make this equation right, coefficients must be added in front of molecules, so number of atoms in right and left are equal.

2O₂ + CH₄ = CO₂ + 2H₂O

How, you have 4 atoms of oxygen, 1 atom of carbon and 4 atoms of hydrogen on both side of reaction.