The empirical and molecular formula : Mg₃Si₂H₂O₈ and Mg₆Si₄H₄O₁₆
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 =
[tex]\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[/tex]
So empirical formula :
[tex]\tt Mg_3Si_2H_2O_8[/tex]
(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