How much oxygen is required under normal conditions to burn 100 grams of heptane?

Let’s compose the equation for the reaction of the interaction of heptane with oxygen:
C7H16 + 11O2 = 7CO2 + 8H2O;

Let’s find the molecular weight of heptane:
12 * 7 + 16 = 100 g / mol;

Let’s find the amount of substance in heptane:
100/100 = 1 mol;

There is a coefficient in front of oxygen, which is 11 times higher than in front of heptane. This means that the amount of substance in oxygen is 11 mol. Let’s find the volume of oxygen:
22.4 * 11 = 246.4 liters;

Answer: the volume of oxygen is 246.4 liters.