Question

What is the empirical formula of a substance that is 53.5% C, 15.5% H, and 31.19% N by weight?

Answer 1

Empirical formula is
`C_2H_7N` and it is Ethylamine.

Step-by-step explanation:

Given that,

A substance consists of 53.5% C, 15.5% H, and 31.19% N by weight. We need to find the empirical formula of a substance.

The atomic masses of each component are as follows :

Carbon, C = 12.011 g/mol

Hydrogen, H = 1.00794 g/mol

Nitrogen, N = 14.01 g/mol

Percentage of carbon,
`C=(53.5)/(12.011 )=4.45\ mol`

Percentage of hydrogen,
`H=(15.5)/(1.00794 )=15.37\ mol`

Percentage of nitrogen,
`N=(31.19)/(14.01 )=2.22\ mol`

To get the empirical formula of the substance, we divide each element by the lowest number of moles i.e. 2.22 mole

`C=(4.45)/(2.22)=2`

`H=(15.37)/(2.22)=6.923\approx 7`

`N=(2.22)/(2.22)=1`

So, there are 2 molecules of carbon, 7 molecules of hydrogen and 1 molecule of nitrogen. Hence, the empirical formula of a substance is
`C_2H_7N` and it is Ethylamine. Hence, this is the required solution.