The empirical formula of a group of compounds is CHCl. Lindane, a powerful insecticide, is a member of this group. The molar mass of lindane is 290.8. How many atoms of carbon does a molecule of lindane contain?

Question

Quizplus · Accepted Answer

Since the empirical formula is CHCl, we know that there is only one carbon atom in each molecule of the compound. To find the number of carbon atoms in the molecular formula, we need to calculate the molecular formula mass and compare it to the empirical formula mass. 
The empirical formula mass can be calculated by adding the atomic masses of one carbon atom, one hydrogen atom, and one chlorine atom: 
Empirical formula mass = (1 x 12.01) + (1 x 1.01) + (1 x 35.45) = 48.47 g/mol
To calculate the molecular formula mass, we divide the molar mass by the empirical formula mass and round to the nearest whole number: 
Molecular formula mass = (290.8 g/mol) / (48.47 g/mol) = 6
Therefore, there are 6 carbon atoms in each molecule of lindane.

The Empirical Formula of a Group of Compounds Is CHCl