When a chemical equation is balanced, it will have a set of whole number coefficients that cannot be reduced to smaller whole numbers. What is the coefficient for O₂ when the following combustion reaction of a hydrocarbon is balanced? ___ C₇H₁₄ + ___ O₂ $\rarr$ ___ CO₂ + ___ H₂O A)42 B)21 C)11 D)10 E)none of these

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First, balance the carbons by placing a coefficient of 10 in front of CO and CO2. This gives us: C10H114S10 + O2 -> 10CO2 + 5H2O Next, balance the hydrogens by placing a coefficient of 57 in front of H2O. This gives us: C10H114S10 + O2 -> 10CO2 + 57H2O Finally, balance the oxygen by placing a coefficient of 26 in front of O2. This gives us: C10H114S10 + 26O2 -> 10CO2 + 57H2O Now we can see that the coefficient for O₂ is 26, and the coefficient for H₂O is 57/2 (which cannot be reduced to a whole number). The closest whole number coefficient for H₂O is 28, which gives us the overall balanced equation: C10H114S10 + 26O2 -> 10CO2 + 28H2O + 2SO2

When a Chemical Equation Is Balanced, It Will Have a Set