Question

A compound with the empirical formula C2HF4 was found to have a molar mass of about 200g/mole. What is the molecular formula of the compound?

Answer 1

`C_4H_2F_8` is the molecular formula of the compound.

Step-by-step explanation:

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

`n=\frac{\text{molecular mass}}{\text{empirical mass}}`

We are given:

Mass of molecular formula = 200 g/mol

Mass of empirical formula of
`C_2HF_4` :

2 × 12 g/mol + 1 × 1 g/mol + 4 × 19 g/mol = 101 g/mol

Putting values in above equation, we get:

`n=(200 g/mol)/(101 g/mol) =1.9 \approx 2`

Multiplying this valency by the subscript of every element of empirical formula, we get:

`C_((2* 2))H_((1* 2))F_((4* 2))=C_4H_2F_8`

`C_4H_2F_8` is the molecular formula of the compound.