Question

The empirical formula of a compound is CH2O. it's molecular weight is 90 . calculate the molecular formula if the compound

Answer 1

Answer:

Molecular formula of the compound is $C_{3} H_{6} O_{3}$

Explanation:

The empirical formula of the compound = $CH_{2} O$

Therefore the empirical formula mass = 30

Here we know that the molecular formula mass = 90

Molecular formula = n × Emperical formula

n= molecular formula mass ÷ empirical formula mass

so, n = $\frac{90}{30}$ = 3

Therefore the molecular formula  =  3 × $CH_{2} O$ = $C_{3} H_{6} O_{3}$

The molecular formula of the compound is $C_{3} H_{6} O_{3}$

Answer 2

Answer:

The molecular formula of the compound with empirical formula $CH_{2} O$ and molecular weight 90 is $C_{3} H_{6} O_{3}$.

Explanation:

Given that empirical formula of the compound = $CH_{2} O$

There are 1 carbon, 2 hydrogen and 1 oxygen atoms

∴Empirical formula mass = (12 * 1) + (1 * 2) + (16 * 1)

                                         = 30

Given that the molecular weight of the compound = 90

Molecular formula = n* empirical formula

n = molecular mass / empirical formula mass

n = $\frac{90}{30}$

  = 3

Thus molecular formula = 3 * $CH_{2} O$

                                        = $C_{3} H_{6} O_{3}$

So the molecular formula of the compound is $C_{3} H_{6} O_{3}$.