Question

What volume of carbon dioxide is produced at STP when 5 litres of propane is burnt completely according to the equation given below?

\[\ce{C3H8 + 5O2 -> 3CO2 + 4H2O}\]

Options

• 10 litres

• 15 litres

• 20 litres

• 25 litres

Answer 1

15 litres

Explanation:

According to Gay-Lussac’s Law, the volume ratio of gases in a reaction is the same as their stoichiometric coefficients. At the same temperature and pressure, equal volumes of gas contain equal numbers of molecules, so gas volumes follow the stoichiometric mole ratios. 

From the balanced equation, 1 volume of C₃H₈ produces 3 volumes of CO₂.

Therefore 5 litres C₃H₈ produces 5 × 3 = 15 litres CO₂.