Final answer:
To find the mass of water produced by combustion of octane, the stoichiometry of the chemical reaction is used, but the specific mass cannot be calculated without additional information about the mass of octane combusted.
Step-by-step explanation:
To determine what mass of water is formed when octane combines with oxygen, we need to follow the stoichiometry of the balanced chemical equation for the combustion of octane (C8H18). According to the balanced equation (assuming complete combustion), 2 moles of C8H18 react with 25 moles of O2 to produce 16 moles of CO2 and 18 moles of H2O (2C8H18 + 25O2 → 16CO2 + 18H2O). Using the molar mass of water (H2O), which is 18.016 g/mol, we can calculate the mass of water produced from a specific amount of octane combusted.
However, we need more details, such as the mass of octane burned, to provide a specific answer to the question. Since these details are not provided in the question, we cannot accurately calculate the mass of water formed without additional information.