Question

Determine the empirical and molecular formula for chrysotile asbestos. Chrysotile has the following percent composition: 28.03% Mg, 21.60% Si, 1.16% H, and 49.21% O. The molar mass for chrysotile is 520.8 g/mol

Answer 1

The empirical and molecular formula : Mg₃Si₂H₂O₈ and Mg₆Si₄H₄O₁₆

Further explanation

Given

28.03% Mg, 21.60% Si, 1.16% H, and 49.21% O

Required

The empirical and molecular formula

Solution

Mol ratio : Mg : Si : H : O =

$\tt \dfrac{28.03}{24}\div \dfrac{21.6}{28}\div \dfrac{1.16}{1}\div \dfrac{49.12}{16}\\\\1.17\div 0.771\div 1.16\div 3.07\\\\1.5\div 1\div 1.5\div 4\\\\3\div 2\div 2\div 8$

So empirical formula :

$\tt Mg_3Si_2H_2O_8$

(Emprical formula)n=molecular formula

(Mg₃Si₂H₂O₈)n=520.8

(24.3+28.2+2.1+8.16)n=520.8

(258)n=520.8⇒n=2

The molecular formula : Mg₆Si₄H₄O₁₆