Calculate the mass of Octane needed to release 6.20 mol Co2

The combustion reaction of octane is as follow,

C₈H₁₈ + 25/2 O₂ → 8 CO₂ + 9 H₂O

According to balance equation,

8 moles of CO₂ are released when = 114.23 g (1 mole) Octane is reacted

So,

6.20 moles of CO₂ will release when = X g of Octane is reacted

Solving for X,

X = (114.23 g * 6.20 mol) : 8 mol

X = 88.52 g of Octane

Result:

88.52 g of Octane is needed to release 6.20 mol CO₂.