Question

How many grams of `Fe_2O_3` are there in 0.500 mole of `Fe_2O_3`?

Answer 1

0.500 moles `xx` molar mass of `Fe_2O_3` = ??

Explanation:

Assume that:
n = number of moles
m = mass of substance
M = molar mass (equivalent to atomic weight on the periodic table)
`n = m -: M`

0.500 moles has been given to you

Now you need to find the molar mass of `Fe_2O_3`. Before you do that, you gotta know what elements are present. If you look closely, you can see that Iron (Fe) and Oxygen (O) is present.

If you refer to your periodic table, Iron has a molar mass of 55.9 g/mol whereas Oxygen has the molar mass of 16.0 g/mol.

Since there are 2 Iron and 3 Oxygen, the molar mass of `Fe_2O_3` is:
[`2 xx 55.9 + 3 xx 16.0`] = 159.8 g/mol.

Therefore the mass of `Fe_2O_3` is:
[m = 159.8 g/mol `xx` 0.500 moles] = 79.9 grams.

79.9 grams are in 0.500 moles of `Fe_2O_3.`