Question

Given the equation: 2C8H18 + 25O2->16CO2 + 18 H2O, 1.0.150 mol of octane is allowed to react with 0.620 mol of oxygen, what is the limiting reactant?

Answer 1

Oxygen is the limiting reactant.

Explanation:

Wiki says:
"The limiting reagent (or limiting reactant) in a chemical reaction is the substance that is totally consumed when the chemical reaction is complete. The amount of product formed is limited by this reagent, since the reaction cannot continue without it. If one or more other reagents are present in excess of the quantities required to react with the limiting reagent, they are described as excess reagents or excess reactants."

Asuming that the rectlng number of mole of oxygen as `1.015mol` we proceed our discussion.

Here as per given balanced reactiom 2 moles of octane completely reacts with 25moles
Of oxygen.
So 1.015 moles octane requires
`(25*1.015)/2=12.6875mol` oxygen
But the given amount of oxygen is `0.62mol` which is less than the required amount 12.6875 mol.
So we can say oxgen will be fully consumed.
Hence Oxygen is the limiting reagent or reactant in this case.