What is the empirical formula for perfluoropropane if the compound contains 81% fluorine and 19% carbon by mass?

1 Answer
Mar 29, 2018

C3F8

Explanation:

As always with the problems it is useful to assume an 100g mass of compound, and then interrogate the atomic composition...

Moles of fluorine=81g19.0gmol1=4.26mol.

Moles of carbon=19g12.011gmol1=1.59mol.

We then divide thru by the LOWEST molar quantity to get a trial empirical formula of ....C1.59mol1.59molF4.26mol1.59mol=CF2.68...

But we know by specification, that the empirical formula is the simplest WHOLE number ratio....and so we mulitply by three to get...C3F8...perfluoropropane...this is the old Freon 218...and you must have twisted some analyst's arm to make the determination.