Question

What volume of oxygen gas (O₂) measured at 0°C and 1 atm, is needed to burn completely 1 L of propane gas (C₃H₈) measured under the same conditions?

(a) 5 L 

(b) 10 L 

(c) 7 L 

(d) 6 L

Answer 1

Ans. (a) 5L

Sol.

C₃H₈ + O₂ ⇒ CO₂ + H₂O 

balancing eqn - C₃H₈ + 5O₂ ⇒ 3CO₂ + 4H₂O 

 

1 mole C₃H₈  -> 5 mole O₂ 

22.4 L C₃H₈  -> 5 x 22.4 L = 112 L O₂ 

1 L C₃H₈  -> 112/22.4 = 5 L  O₂