Question

A compound has an empirical formula C₂H4S.
What is its molecular formula, if its molar
mass is 168 g/mol?

Answer 1

• The atomic mass of carbon is 12.011 g/mol.
• The atomic mass of hydrogen is 1.00794 g/mol.
• The atomic mass of sulfur is 32.06 g/mol.

This means that the molar mass of $\text{C}_{2}\text{H}_{4}\text{S}$ is

$2(12.011)+4(1.00794)+32.06=60.11376$

Dividing this by the given molar mass, we get $\frac{168}{60.11376} \approx 3$

So, the molecular formula is about $\boxed{\text{C}_{6}\text{H}_{12}\text{S}_{3}}$