Question

the empirical formula of a compound of molecular mass 120 is ch20

Answer 1

molecular mass of (CH2O)n = 30n = 120
n = 4

so, the molecular formula of the compound will be C4H8O4

Answer 2

Answer: Molecular formula will be $C_4H_8O_4$

Explanation:

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

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

To calculate the molecular formula, we need to find the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is:

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

empirical mass of $CH_2O$= $1\times 12+2\times 1+1\times 16=30$

Molecular mass= 120

$n=\frac{120}{30}=4$

Thus molecular formula will be $4\times CH_2O=C_4H_8O_4$