One form of asbestos called chrysotile is considered to be a human carcinogen. Mass analysis shows that the composition of chrysotile is 26.3% Mg, 20.2% Si, 1.45% H, and the remainder of the mass is oxygen. Determine the empirical formula of chrysotile. A)MgSiHO₃ B)Mg₂Si₂H₂O₅ C)Mg₃Si₂H₄O₆ D)Mg₃Si₂H₄O₉ E)Mg₄Si₃H₅O₉

Question

Quizplus · Accepted Answer

To find the empirical formula, we first convert the mass percentages to moles by dividing by the atomic mass of each element: Mg (24.305), Si (28.085), H (1.008), and O (15.999). For Mg: 26.3% / 24.305 ≈ 1.08 moles, for Si: 20.2% / 28.085 ≈ 0.72 moles, for H: 1.45% / 1.008 ≈ 1.44 moles. The mass percentage of O is found by subtracting the sum of the mass percentages of Mg, Si, and H from 100%, which gives 52.05%. Thus, for O: 52.05% / 15.999 ≈ 3.25 moles. To find the simplest whole number ratio, divide each mole value by the smallest mole value found (0.72): Mg ≈ 1.5, Si ≈ 1, H ≈ 2, O ≈ 4.5. Since we cannot have half atoms in an empirical formula, we multiply each ratio by 2 to get whole numbers, resulting in Mg3Si2H4O9, which corresponds to the given option.

One Form of Asbestos Called Chrysotile Is Considered to Be