What is the percentage by mass of iron (Fe) in the mineral hematite (#Fe_2O_3#)?

1 Answer
Dec 5, 2016

Answer:

69.9% to three significant figures.

Explanation:

First find the total mass of the compound

# 3xx 15.999 = 48 # grams for Oxygen

# 2 xx 55.8 = 111.6# grams for Iron

adding these gives 159.6 grams per molecules # Fe_2O_3#

Now divide the mass of Iron by the total mass for the compound.

# 111.6/159.6 = .6992481# Change this to a percentage by multiplying by 100 and round off to three significant figures gives

69.9 % Iron.