The octane rating of gasoline is a relationship of the burning efficiency of the given gasoline mixture to the burning efficiency of octane (CgH18). Like most hydrocarbons, octane reacts with oxygen gas to produce carbon dioxide and water. The unbalanced equation for this reaction is
Cs H18 (g) + 02(g) CO2(g) + H20(g)
After the reaction, how much octane is left?
To determine how much octane is left after the reaction, we first need to balance the chemical equation:
Cs H18 (g) + aO2(g) -> bCO2(g) + cH2O(g)
Balancing the equation, we get:
2 C8H18 (g) + 25 O2(g) -> 16 CO2(g) + 18 H2O(g)
From the balanced equation, we can see that 2 moles of octane (C8H18) react with 25 moles of oxygen gas (O2) to produce 16 moles of carbon dioxide (CO2) and 18 moles of water (H2O).
If x moles of octane react, it will produce:
16x/2 = 8x moles of CO2
18x/2 = 9x moles of H2O
So, the amount of octane left after the reaction will be:
2 moles - x moles = 2 - x moles