You are asked to make 10 moles of iron (Fe) from iron oxide (fe203) and excess carbon monoxide (CO).
Fe203 (s) + 3CO (g) -- 2Fe(I) + 3CO2(g)
How many moles of iron oxide must you use?
5 moles
2 moles
10 moles
3 moles

5 moles.
think about the ratio of moles of iron oxide (Fe2O3) and iron (Fe) in that balanced chemical equation, which is 1:2, respectively. if there are 10 moles of Fe, you would divide that by 2 to get the number of moles of Fe2O3.

Ithink is a because if say increased in electronegativity