Answer to Question #56899 in General Chemistry for Buono11

Question

A 1.0876 g sample of compound “B” contain C, H and O atoms was quantitatively burned in excess oxygen. The carbon dioxide and the water vapor were trapped and their mass was determined. The mass of the CO2 was 2.078 g and the mass of the H2O was 1.2738 g. What is the empirical formula of this compound?

Answer 1

C_xH_yO_z + O₂ = xCO₂ + (y/2)H₂O
n(C ) = 2.078 / 44 = 0.0472 (mol);
n(H) = 1.2738 / 18 = 0.0708 (mol);
n(O) = (1.0876 – (0.0472 * 12) – (0.0708 * 1)) / 16 = 0.02813;
C : H : O = 0.0472 : 0.0708 : 0.02813 = 1.668 : 2.5167 : 1 = 10 : 15 : 6;

Answer: C₁₀H₁₅O₆