Question

A substance has an empirical formula of CH2Br and a molar mass of 188 g mol-1 . What is the molecular formula of the compound?

Answer 1

M(CH₂Br)=12.0+2*1.0+79.9=93.9 g/mol

M=188 g/mol

N=M/M(CH₂Br)

N=188/93.9=2

C₂H₄Br₂

Answer 2

Answer : The molecular of the compound is,
`C_2H_4Br_2`

Explanation :

The Empirical formula =
`CH_2Br`

The empirical formula weight = 1(12) + 2(1) + 1(80) = 94 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

`n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}`

where,

n = valency factor

Now put all the given values in this formula, we get:

`n=(188)/(94)=2`

Molecular formula =
`(CH_2Br)_n=(CH_2Br)_2=C_2H_4Br_2`

Therefore, the molecular of the compound is,
`C_2H_4Br_2`