The rock in a particular iron ore deposit contains 78% Fe2O3 by mass. How many kilograms of the rock must a mining company process to obtain 1.0 × 103 kg of iron?

Solution 111P

Here, we are going to calculate the mass of rock required by the mining company to obtain 1.0 x 103 kg of iron.

Step 1:

Molar mass of Fe2O3 = (2 x atomic mass of Fe) + (3 x atomic mass of O)

= (2 x 55.845) + (3 x 15.9994)

= 111.69 + 47.9982

= 159.6882 g/mol

Step 2:

Now, mass percentage of Fe in Fe2O3 = (111.69 / 159.6882) x 100

= 69.9 %

I.e., in one kg of Fe2O3, (69.9/100 = 0.699) kg of Fe is present.