According to the following (unbalanced) reaction:

Question

Fe(s) + Cl2 (g) ----> FeCl3 (s)

How many milligrams of iron(III) chloride result when 14.50 mg of iron is reacted with an excess of chlorine gas?

??? mg FeCl3

Answer 1

The balanced equation is 2 Fe + 3Cl2 ======= > 2 FeCl3.

The conversion factor is 2 x mol. mass of FeCl3 / 2 x atomic mass Fe = 2 x 162.195 / 2 x 55.845 = 2.904 mg FeCl3 for every mg of Fe reacted.

mg FeCl3 produced = 2.904 x 14.50 = 42.11 mg

Usually reaction masses are expressed in grams, but mg will work as long as all units are expresses in mg.