Lindane is a toxic insecticide that causes dizziness and diarrhea in humans.Find the molecular formula for lindane given its percent composition: 24.78% C,2.08% H,and 73.14% Cl.The approximate molar mass is 290 g/mol.

Question

Quizplus · Accepted Answer

To determine the molecular formula of lindane, we need to determine the empirical formula first, which represents the simplest whole number ratio of atoms in a compound.

Assuming a 100 g sample, we can calculate the mass of each element in the sample:

- Mass of C: 24.78 g 
- Mass of H: 2.08 g 
- Mass of Cl: 73.14 g

Next, we need to convert these masses to moles:

- Moles of C: 24.78 g / 12.01 g/mol = 2.064 mol 
- Moles of H: 2.08 g / 1.01 g/mol = 2.059 mol 
- Moles of Cl: 73.14 g / 35.45 g/mol = 2.065 mol

The empirical formula will then be the simplest whole number ratio of the moles, which is approximately C₆H₆Cl₆.

To determine the molecular formula, we need to know the molar mass of the compound. The approximate molar mass of lindane is given as 290 g/mol.

We can calculate the empirical formula mass of C₆H₆Cl₆:

- Empirical formula mass = (6 x 12.01 g/mol) + (6 x 1.01 g/mol) + (6 x 35.45 g/mol) = 288.84 g/mol

The molecular formula will be a whole number multiple of the empirical formula, such that:

- Molecular formula mass = (empirical formula mass) x n 
- where n is a whole number

We can calculate n by dividing the approximate molar mass by the empirical formula mass:

- n = 290 g/mol / 288.84 g/mol ≈ 1

This means that the molecular formula is approximately the same as the empirical formula, which is C₆H₆Cl₆ or D) C₆H₆Cl₆.

Lindane Is a Toxic Insecticide That Causes Dizziness and Diarrhea