To determine the mole ratio of oxygen (O₂) to pentane (C₅H₁₂) in the combustion reaction, we look at the balanced chemical equation provided:
[tex]\[ \text{C}_5\text{H}_{12} + 8\text{O}_2 \rightarrow 5\text{CO}_2 + 6\text{H}_2\text{O} \][/tex]
A balanced chemical equation shows the stoichiometric coefficients in front of each substance, indicating the number of moles of each reactant and product involved in the reaction. Here, the coefficients are as follows:
- 1 mole of C₅H₁₂
- 8 moles of O₂
- 5 moles of CO₂
- 6 moles of H₂O
We need to find the mole ratio of oxygen (O₂) to pentane (C₅H₁₂). The coefficients directly provide this ratio. Specifically, for every 1 mole of C₅H₁₂, there are 8 moles of O₂ reacting.
Thus, the mole ratio of oxygen (O₂) to pentane (C₅H₁₂) is:
[tex]\[ 8 : 1 \][/tex]
So, the correct answer is:
[tex]\[ \boxed{8 : 1} \][/tex]