Select the correct balanced equation for the combustion of methane.
CH4 + 02 -> CO 2 + H2O

A: CH4 + 2O2 -> CO2 + 2H2O

Explanation:

Count how many elements they are in all molecules for the reactants and for the products.

C = 1 element

H = 4 elements

O = 2 elements

C = 1 element

O = 2 elements

H = 2 elements

O = 1 element

2 oxygen atoms + 1 oxygen atoms = 3 oxygen atoms total on the products side.

To balance this equation, we need to add 2 more elements of hydrogen and 2 more elements of oxygen. Therefore, we add a 2 to the coefficient of O2 for the reactants side and add a 2 to the coefficient of H2O for the products side.

Now let us try it.

Count how many elements they are in all molecules for the reactants and products.

C = 1 element

H = 4 elements

O = 4 elements

C = 1 element

O = 2 elements

H = 4 elements

O = 2 elements

2 oxygen atoms + 2 oxygen atoms = 4 oxygen atoms total on the products.

All of the elements are balanced.

Hope it helped!