Question

Methane (CH4) is the main component of natural gas. It is burned for fuel in a combustion reaction. The unbalanced combustion reaction for methane is shown below. CH4 + O2 CO2 + H2O + heat When the reaction is balanced, how many carbon dioxide molecules are produced for every methane molecule burned?

Answer 1

In order to balance reactions, we need to remember that both sides of the reaction should have the same number of atoms. This is to agree with the law of conservation of mass where it states that the sum of the mass inflow of a process should be equal to the sum of the mass out in the process since mass cannot be created or destroyed. We write the equation as

CH4 + O2 = CO2 + H2O

Reactant side       Product side
C = 1                            1
H = 4                            2
O = 2                            3

We need to balance the atoms. It should be as follows:

CH4 + 2O2 = CO2 + 2H2O

Answer 2

Answer: 1 molecule of carbon dioxide is produced for every methane molecule.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The balanced chemical reaction for combustion of methane is:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

Thus for every 1 molecule of methane used 1 molecule of carbon dioxide is produced.