Question

What volume of oxygen gas $(O_2)$ measured at $0^\circ C$ and 1 atm, is needed to bum completely 1L of propane gas $(C_3H_8)$ measured under the same conditions?

• A. 7 L
• B. 6 L
• C. 5 L
• D. 10 L

Answer 1

The Correct Option is C

To solve this problem, we need to determine the amount of oxygen gas $(O_2)$ required to completely combust 1 liter of propane gas $(C_3H_8)$ under standard conditions. The reaction for the combustion of propane is given by:

C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O

This balanced chemical equation tells us the stoichiometric ratio between propane and oxygen. Specifically, 1 mole of propane reacts with 5 moles of oxygen to produce 3 moles of carbon dioxide and 4 moles of water.

According to Avogadro's Law, under the same conditions of temperature and pressure, equal volumes of gases contain an equal number of moles. Thus, from the stoichiometric relationship:

• 1 liter of C_3H_8 reacts with 5 liters of O_2.

Therefore, to burn 1 liter of propane completely, we need 5 liters of oxygen gas.

Hence, the correct answer is:

• 5 L