In what mass of magnetic iron ore Fe2O3 contains 2 tons of Fe. Mass fraction of impurity 20% alkali solution?

Given:
m (Fe) = 2 t;
ω = 20 percent;
ω = 0, 2;
Find the mass m (Fe2 O3);
Solution:
1) The molecular weight of Fe2 O3 is: Mr (Fe2 O3) = 56 * x ^ 2 + 16 * x ^ 3 = 112 + 48 = 160;
2) The mass fraction of iron Fe in Fe2 O3 is: ω (Fe) = Mr (Fe) / Mr (Fe2 O3) = 112/160 = 0.7;
3) The mass of Fe2 O3 is: m (Fe2 O3) = m (Fe) / ω (Fe) = 2/0, 7 = 2, 857 t;
4) The mass of Fe2 O3 with a mass fraction of 0, 2 is equal to:
2.857 t. Fe2 O3 = 0.8;
Xt. Fe2 O3 = 1;
Hence, X = 2.857 * 1 / 0.8 = 2.857 / 8 = 3.571 t;
Answer: m (Fe2 O3) = 3.571 with a fraction of 0.2.