Question

30.

If 30.1 grams of Hg combines completely with 12.0 grams of Br to form a compound, what is the percent composition of Hg in the compound?

A.



60.1%


B.



39.9%


C.



71.5%


D.



28.5%

Answer 1

C. 71.5% - Because the total mass of both would be 30.1 g + 12.0 g = 42.1 g.
If you want to know the percentage the 30.1 (Hg) is out of 42.1 g (both), you just do 30.1/42.1 = 0.7149, which would be the same as 71.5%