An ore contains Fe3O4 and no other iron. The iron in a 51-gram sample of the ore is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 21.9 g. What was the mass of Fe3O4 in the
sample of ore?
The simple way is to convert mass Fe2O3 into mass Fe3O4 by using a chemical factor (which is not taught anymore).
mass Fe2O3 x (2*molar mass Fe3O4/3*molar mass Fe2O3) = ??
I got 156.356 grams, but it still says that's wrong.
I wonder how you obtained that? Post your work. I don't have anything close to that.
21.9 x (463.07/479.07)=21.1685
Must have done something wrong the first time. Is that right?
Looks ok to me. Now round off to three s.f.
how is the 51 gram sample integrated into the equation then? or is it not used at all in this case?
To find the mass of Fe3O4 in the sample of ore, we need to use the information given about the conversion of iron in the ore.
Let's break down the information given:
1. The initial mass of the sample of the ore: 51 grams.
2. The mass of Fe2O3 obtained after the chemical reactions: 21.9 grams.
Now, we need to understand the stoichiometry of the chemical reaction between Fe3O4 and Fe2O3.
The balanced chemical equation for the conversion of Fe3O4 to Fe2O3 is:
3 Fe3O4 -> 4 Fe2O3
From the equation, we can see that for every 3 moles of Fe3O4, we obtain 4 moles of Fe2O3.
To calculate the mass of Fe3O4 in the sample, we need to determine the moles of Fe3O4 and then convert it to grams using the molar mass of Fe3O4.
1. Calculate moles of Fe2O3:
Moles of Fe2O3 = Mass of Fe2O3 / Molar mass of Fe2O3
The molar mass of Fe2O3 can be calculated by adding the atomic masses of iron (Fe) and oxygen (O):
Molar mass of Fe2O3 = (2 x Atomic mass of Fe) + (3 x Atomic mass of O)
The atomic masses can be found on the periodic table.
2. Convert moles of Fe2O3 to moles of Fe3O4:
Moles of Fe3O4 = (4/3) x Moles of Fe2O3
3. Calculate mass of Fe3O4:
Mass of Fe3O4 = Moles of Fe3O4 x Molar mass of Fe3O4
The molar mass of Fe3O4 can be calculated in a similar way to Fe2O3, considering the atomic masses of iron (Fe) and oxygen (O) in Fe3O4.
By following these steps and performing the necessary calculations, you will find the mass of Fe3O4 in the sample of the ore.