Question

21) 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:

Two bromines mole wt = 2 * 79.9 = 159.8 gm (from periodic table)

Mg = 24.3 gm

159.8 / ( 159.8 + 24.3) = .868 = 86.8 %