Calculate the mass of iron in 10 kg of iron ore which contains 80% of pure ferric oxide.

The amount of iron in ( 160 g) = 2 $\times$ 56 = 112 g
So, in 10 kg (10000 g) of = $\times$ 10000 =7000g
For 100 % purity of 10 kg , the amount of iron = 7000 g

For 80 % purity = = 5.6 $\times$ g