A certain compound of bromine and fluorine is used to make UF₆, which is an important chemical in the processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. What is its empirical formula? A) BrF B) BrF₂ C) Br₂F₃ D) Br₃F E) BrF₃

Question

Quizplus · Accepted Answer

Assume we have 100 g of the compound. 58.37 g of those are bromine, leaving 41.63 g for fluorine. 
Convert grams to moles using the molar mass:
- Moles of Br: 58.37 g / 79.904 g/mol = 0.7294 mol Br
- Moles of F: 41.63 g / 18.9984 g/mol = 2.19 mol F
Divide each by the smallest number of moles:
- Br: 0.7294 mol / 0.7294 = 1
- F: 2.19 mol / 0.7294 = 3.00
The empirical formula is BrF3, thus the best choice is E.

A Certain Compound of Bromine and Fluorine Is Used to Make