If I am not mistaken,

(Number of moles)=(mass)/(molar mass)

So, (mass)=(Number of moles)*(molar mass)

Moreover, we uses mole ratio directly from the balanced equation. Take question 2 as an example, you have 300000 mol of Fe_{2}O_{3}. From the balanced equation, mole ratio of Fe_{2}O_{3} and Fe is 1:2, i.e. 1 mol of Fe_{2}O_{3} gives 2 mol of Fe. Thus, 300000 mol of Fe_{2}O_{3} gives 600000 mol of Fe. Then, you have to multiply that 600000 mol of Fe with its molar mass, which is 56. Finally, you get 600000*56=33600000g of Fe, or 33.6 tonnes of Fe.

Please kindly correct me if I have made any mistakes.