Answer: The balanced chemical equation is given below.
Step-by-step explanation:
Combustion reaction is defined as the chemical reaction in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide gas and water molecule.
A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on the product side. These equations follow law of conservation of mass.
The chemical equation for the combustion of octane follows:

By Stoichiometry of the reaction:
1 mole of liquid octane reacts with
moles of oxygen gas to produce 8 moles of carbon dioxide gas and 9 moles of water vapor.
Hence, the balanced chemical equation is given above.