AP Chemistry· difficulty 3/5
A 9.0 g sample of an unknown hydrocarbon is burned, producing 27.5 g of CO₂ and 13.5 g of H₂O. The empirical formula has approximate ratio (C : H)
1 : 1
2 : 5
1 : 3
1 : 2
Explanation
n(C) = 27.5/44 = 0.625 mol; n(H) = 2(13.5)/18 = 1.5 mol. Ratio C:H = 0.625 : 1.5 = 1 : 2.4 ≈ 2 : 5 (close to C₂H₅ → C₄H₁₀, butane).
Want 10 more like this — adaptive to your weak spots?
A compound has empirical formula CH₂O and molar mass 180 g/mol. Its molecular formula is…
chevron_rightA compound contains 40.0% C, 6.7% H, and 53.3% O by mass. Its empirical formula is…
chevron_rightA separate measurement gives a molar mass of 84 g/mol. What is the molecular formula?…
chevron_right