Cyclopropane, a gas containing only carbon and hydrogen, is an anesthetic.
If 0.450 L of cyclopropane at 120°C and 0.720 atm reacts with excess O₂ to give 1.35 L of CO₂(g) and 1.35 L of H₂O(g) at the same temperature and pressure, what is the percent by weight of carbon in cyclopropane?

Question

Quizplus · Accepted Answer

The balanced reaction is C3H6 + 4.5O2 → 3CO2 + 3H2O. From the volumes, 1 mole of C3H6 produces 3 moles of CO2, indicating 3 carbon atoms per molecule. The molar mass of C3H6 is 42 g/mol (3*12 for C + 6*1 for H), and the mass of carbon is 36 g (3*12). The percent by weight of carbon is (36/42)*100% = 85.7%.

Cyclopropane, a Gas Containing Only Carbon and Hydrogen, Is an Anesthetic