A balanced chemical equation shows the number of particles of each substance involved in a chemical reaction. Such an equation includes formulas and coefficients. The formulas include symbols for each type of atom in the substance. The coefficients are the numbers present in front of the formulas. The act of balancing a chemical equation involves selecting the lowest possible set of coefficients that would provide the same number of atoms of each element on the reactant and the product side of the equation.
 

To be successful with this question, you need to know what a balanced chemical equation involves. You also need to have a good strategy for how to balance a chemical equation. The two infographics below describe these two ideas. Study the graphics, giving particular attention to the Step-by-Step Balancing Method  and the Example in the second infographic. Some specific information regarding this question are provided after the second infographic.

 

Some Specifics About This Question Group

The two versions of questions in this Question Group are similar. They each involve combustion reactions. A hydrocarbon is reacted with oxygen; the products are CO₂ and H₂O. There are three elements that must be balanced - C, H, and O. Since the element O shows up in two formulae on the product side, it would be best to start by balancing either C or H first. Balance one of these elements; then balance the other element.  Once the elements C and H have been balanced, direct your attention to the balancing of O. This can be done by inserting a coeffiient in front of O₂ on the reactant side.  Once done, conduct an atom count to insure accuracy and completion.