Question

Calculate the molecular formula of a compound that contains 34.5 g of carbon and 5.76 of hydrogen and has a molecular weight of 56.

Answer 1

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Answer on Question #46418, Chemistry, Other

Task:

Calculate the molecular formula of a compound that contains 34.5 g of carbon and 5.76 of hydrogen and has a molecular weight of 56.

Answer:

M (C) = 12 g/mol

M (H) = 1 g/mol

$$C = \frac{34.5\,g}{12\,g/mol} = 2,875\,mol$$ $$H = \frac{5.76\,g}{1\,g/mol} = 5.76\,mol$$

The calculated ratio on a compound is H:C=2:1. So, the empirical formula is CH₂.

The molar mass of this fragment will be: M(CH₂) = 14 g/mol.

As it had been said, molecular weight of a compound is 56.

So, the amount of fragments will be: n=56/14=4.

The molecular formula of a compound is C₄H₈.