M4 Periodic Table: Chemical Equations
Slide 18 of 30
Balancing a chemical equation by trial and error method
CH4 + O2 ®  CO2 + H2O
A chemical equation is balanced by adding coefficients in front of the chemicals.
1. Begin by balancing elements that occur in only one substance on each side
–In this example C or H.
–C is already balanced and there are 4 H on the left but only 2 on the right.
–The number of H atoms on the right can be increased to 4 by multiplying it by 2 (by adding the coefficient 2).
–Add 2 in front of H2O (and not change H2O to H4O).
CH4 + O2 ®  CO2 + 2H2O