When iron reacts with oxygen at high temperatures, a magnetic iron oxide is produced:

3Fe + 2O2 = Fe3O4

a. How many moles of iron and oxygen are required to produce 10 moles of magnetic iron oxide? (4 marks)
b. How many moles of oxygen are required to react with 30 moles of iron? (2 marks)
c. If a reaction is brought about between 60 moles of iron and 60 moles of oxygen,
i) which reactant will be in excess and by how many moles?
ii) calculate the number of moles of magnetic iron oxide produced.