A)1.75×3 moles of carbon monoxide
B)2:3
A)each mole of ferric oxide requires 3 moles of carbon monoxide. Therefore 1.75 moles requires 1.75 ×3 moles of carbon monoxide
Convert mols to grams by multiplying grams of tin by the number of mols.
There are 119 grams per mol
119 x 11.8 = 1404 grams
Pure magnesium's formula would just be Mg because all elements except for 7 nonmetals are just left alone when they are by themselves in a formula. The 7 diatomic elements( means they have to have two of them without another element attached to it aka. a subscript two after it when it's by itself) are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. An easy way to remember the diatomic seven is that when looking at a periodic table if you trace over them from nitrogen over to fluorine and down to iodine all of those elements are diatomic + hydrogen.
And your unbalanced and balanced equations are correct.
(sorry I went on a tangent with the diatomic rules hopefully it will help you in the future though)