Final answer:
The question does not provide enough information to determine how much octane is left after the reaction.
Step-by-step explanation:
The question asks about the amount of octane left after the reaction has occurred. To determine this, we need to know the balanced equation for the reaction and the amount of octane initially present. The given equation is 2 C8H18(g) + 25 O2(g) → 16 CO2(g) + 18 H2O(g), which shows that for every 2 molecules of octane burned, 16 molecules of CO2 are generated. Unfortunately, the amount of octane initially present is not provided in the question, so we cannot determine how much is left after the reaction.