Question

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

Answer 1

Answer: The empirical formula is $BrF_3$

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of Br=  58.37 g

Mass of F = (100-58.37) = 41.63 g

Step 1 : convert given masses into moles.

Moles of Br=$\frac{\text{ given mass of Br}}{\text{ molar mass of Br}}= \frac{58.37g}{80g/mole}=0.73moles$

Moles of F =$\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{41.63g}{19g/mole}=2.2moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Br = $\frac{0.73}{0.73}=1$

For F = $\frac{2.2}{0.7}=3$

The ratio of Br: F= 1 : 3

Hence the empirical formula is $BrF_3$