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
Edmund Liew ยท Grace
May 24, 2016

(CFBrO)xx 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. 381.01/126.9 = 3.00
Rounded to nearest whole number

Now, multiply the whole number by the Empirical Formula.
Like this (CFBrO)xx 3 = C_3F_3Br_3O_3.

Therefore your molecular formula is C_3F_3Br_3O_3.

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