How many grams of iron are in 79.2 g of iron (Ill) oxide?

1 Answer
Feb 27, 2017

Answer:

#"Mass of iron "~=# #"55"*"g"#

Explanation:

We calculate (i) a molar quantity of iron oxide:

#(79.2*g)/(159.69*g*mol^-1)=0.496*mol#.

And then (ii) convert this molar quantity into a mass of iron:

#"Mass of iron"=2xx0.496*molxx55.85*g*mol^-1=55.4*g#.

Why did I multiply the molar quantity by 2?