Question

The empirical formula for a compound is CH2. If n is a whole number, which shows a correct relationship between the molecular formula and the empirical formula?

Answer 1

Answer : The correct relationship between the molecular formula and the empirical formula is, $\text{molecular mass}=n\times \text{empirical mass}$

Explanation :

Empirical formula : It is the simplest form of the chemical formula which depicts the whole number of atoms of each element present in the compound.  

Molecular formula : it is the chemical formula which depicts the actual number of atoms of each element present in the compound.  

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 :

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

As we are given that the empirical formula of a compound is $CH_2$.

$\text{molecular mass}=n\times \text{empirical mass}$

Thus, the molecular formula will be, $(CH_2)_n$

Answer 2

Molecular formula = empirical formula * n