Question

What volume of oxygen gas measured at 0°c and 1 atm,is needed to burn completely 1 l,of propane gas measured under the same conditions?

Answer 1

Burning of propane:

C3H8 + 5O2 → 3CO2 + 4H2O

1 mole 5 mole

(at STP) 22.4 L 5X22.4 L

So at STP,

to burn 22.4 L propane 5X22.4 L oxygen is needed

to burn 1 L propane 5X22.4/22.4 L oxygen is needed = 5 L oxygen is needed

or

First write a balanced equation:

C3H8 + 5 O2 = 3 CO2 + 4 H2O

If the propane and oxygen gases are at the same conditions of temperature and pressure :

1 litre of C3H8 will require 5