Limiting Reactant and Theoretical Yield?

Question

I am having a really touch time trying to figure out how do this problem so can somebody please help explain it to me.


If 5.00g magnesium is combined with 10.0g of chlorine, show by calculation which substance is the limiting reactant, and calculate the theoretical yield of magnesium chloride for the reaction.

ok I understand how you did everything but what does m=5 for mg and m=cl2 for cl2 what does m stand for

Answer 1

First find the quantities of Mg and Cl2 in moles. Atomic mass of Mg equals Am = 24 and Molar mass of Cl2 equals Mm = 71:

moles of Mg: n = m/Am(Mg) = 5/24 = 0.21 mol approx.

moles of Cl2: n = m/Mm(Cl2) = 10/71 = 0.141 mol approx.

According to the chem. equation:

Mg + Cl2 --> MgCl2

one mole of Mg reacts with one mole of Cl2. So the Cl2 is the limiting reactant and the reaction produces 0.141 mol of MgCl2.