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?
- 5 L
- 10 L
- 7 L
- 6 L
Answer
(1) 5 L
Solution
Combustion of propane:
C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(l)
∵ By Gay-Lussac's law (Avogadro's law), at the same temperature and pressure, volumes of reacting gases are in the ratio of their stoichiometric coefficients.
⇒ 1 L of C3H8 needs 5 1 = 5 L of O2.
Answer: (1)