What is the molecular formula of a compound if its empirical formula is CFBrO and its molar mass is 381.01 g/mol?

1 Answer
May 24, 2016

(CFBrO)× 3 = ??

Explanation:

Molar mass of compound (381.01 g/mol) has been provided for you.

Now you need to calculate the molar mass of CFBrO.
The molar mass of:
C=12.0 g/mol
F=19.0 g/mol
Br=79.9 g/mol
O=16.0 g/mol

The molar mass of empirical formula, therefore (CFBrO) is:
12.0+19.0+79.9+16.0 = 126.9 g/mol.

In order to get the molecular formula of CFBrO,
divide molar mass of compound by molar mass of empirical formula, like this: molar mass of compound molar mass of empirical formula = whole number

i.e. 381.01126.9 = 3.00
Rounded to nearest whole number

Now, multiply the whole number by the Empirical Formula.
Like this (CFBrO)× 3 = C3F3Br3O3.

Therefore your molecular formula is C3F3Br3O3.