Question

What is the percent by mass of bromine in the compound MgBr₂?A) 13.2%B) 43.4%C) 56.6%D) 86.8%

Answer 1

D) 86.8%

Step-by-step explanation:

It necessary to use the molar mass of Br (80g/mol) and MgBr2 (184g/mol). The MgBr2 is the 100%, so with a mathematical rule of three we can calculate the percent by mass of bromine.

In the molecule of MgBr2 there are 2 bromine, so the total mass of bromine it is 160g (80gx2):

`\begin{gathered} 184g-100\% \\ 160g-x=(160g*100\%)/(184g) \\ x=86.9\% \end{gathered}`

Finally, the percent by mass of bromine is 86.9% (86.8%).