Question

Octane has a density of 0.692g/ml how many grams of O2 is needed to burn down 17 gal of C8H18

Answer 1

1 gal = 3785.41 mL

17 gal = 64352 mL

given that density of octane = 0.692 g/mL

mass of 17 gal octane = 64352 x 0.692 = 44531.584 g

molar mass of octane = 114.23 g/mol

number of moles of octane = mass of octane/molar mass of octane = 44531.584/114.23 = 389.8414 moles

balanced chemical equation is

2 C₈H₁₈ + 25 O₂ give 16 CO₂ + 18 H₂O

one mole octane react with 25/2 (12.5) moles of O2

Thus number of moles of O2 required for the reaction is = 12.5 x 389.8414 = 4873.0175 moles

molar mass of O2 = 32 g/mol

mass of O2 = number of moles x molar mass = 4873.0175 x 32 = 155936.563 g