Question

A compound has an empirical formula of
CHN. What is its molecular formula, if its
molar mass is 135.13 g/mol?
(C=12.01 amu, H=1.008 amu, N=14.01)
A
B
C5H5N5
CG HONG

Answer 1

Explanation:

Given -

molar mass = 135.13 g/mol

To Find -

• molecular formula

Solution:

we know that -

• molecular mass = n × empirical mass

So,

Here empirical mass =

12.01 + 1.008 + 14.01 = 27.028

Then,

135.13 = n × 27.028

n = 4.99 ≈ 5

We know that,

• molecular formula = n × empirical formula

Then,

molecular formula = 5(CHN)

= C₅H₅N₅

Therefore,

Option A is correct✔