Question

When iron metal reacts with oxygen, the reaction can form Fe2O3. Write a balanced chemical equation for this reaction, and find the number of moles of oxygen that are needed to form 6 mol of Fe2O3 while showing your work.

Answer 1

The balanced equation is 
4Fe+3O₂⇒2Fe₂O₃

We know that the mole of Fe₂O₃ is 6, and since the ratio between oxygen and Fe₂O₃ is 3:2, we can see that

3:2 = x:6 (3 oxygen moles can make 2 Fe₂O₃ moles = x oxygen moles can make 6 Fe₂O₃ moles)

Multiply outside and inside (3*6 , 2*x) and put them on opposing sides of the equation

2*x = 3*6
2x=18
x=9
Therefore 9 moles of oxygen is needed.

Answer 2

The reaction Fe203 occurs when oxygen and iron metal react to each other. The complete balanced formula for the chemical equations will be " 4Fe + 302 -> 2 Fe203. You will need to multiply 6 mols by 3/2 (1.5) and that will give the 9 mols needed to find the number of moles of oxygen that are needed.