What molar amount of magnesium will form from the decomposition of 22.33g MgCl2?

Question

The balanced equation is MgCl2= Mg+Cl2

Can some one show me how to set the problem up to find a answer?

Answer 1

okay. So lets find the moles of Mg.

1mol Mg = 24.305g Mg
22.33g Mg = 0.9187 mol Mg

Now lets do the math.

You have the equation MgCl2 ~~> Mg + Cl2
In order to find the moles of MgCl2, we apply simple stoichiometry. Since we need .9187mol Mg, we need 2(.9187) mole Cl. That is 1.837mol. The mass of this is 1.837molCl * 12.011g/mol Cl = 22.07g Cl. 22.07gCl + 22.33g Mg = 44.40g MgCl2.

Therefore you need 44.40g MgCl2 to decompose to make 22.33g Mg, or 1 mole MgCl2 to make 1 mole Mg.. Hope this helps. =)

Answer 2

you have 22.33 g MgCl2 so divide that by the molar mass to get the number of mols of MgCl2

then for every mole of MgCl2 you have you have one mole of Mg so the number of moles of MgCl2 = the number of moles of Mg