C₈H₁₈(g) + 12.5O₂(g) => 8CO₂(g)+ 9H₂O(g) ΔH = -5054kj/mol

Calculate the energy released when 50g of octane burn in oxygen

C = 12, H =1, O =16.

Step 1 Calculate the mole of octane.

50/114 = 0.4386 mole

Step 2 one mole of octane produces 5054kj of energy

so 0.4386 mole of octane will produce (0.4386 / 1) X 5054 = 2216.68kj

Calculate the energy released when 150g of octane burn in oxygen according to the equation above.

C = 12, H =1, O =16.

Step 1 Calculate the mole of octane.

150/114 = 1.316 mole

Step 2 Two mole of octane produce 10108kj of energy

so 1.316 mole of octane will produce (1.316 / 2) X 10108 = 6650kj