12.39 g sample of phosphorus (30.97 g/mol) reacts with 52.54 g of chlorine gas, Cl2

(70.91 g/mol) to form only phosphorus trichloride, PC13 (137.33 g/mol). Which is the

limiting reactant?

P is the limiting reagent

Explanation:

P = phosphorus = 30.97g/mol

Cl2 = Chlorine = 70.91g/mol

PCl3 = Phosphorus Trichloride = 137.33g/mol

P + Cl2 = PCl3

Left Side

P = 1

Cl = 2

Right Side

P = 1

Cl = 3

So equation needs to be balanced first

2P + 3Cl = 2PCl3

Left Side

P = 2

Cl = 6

Right Side

P = 2

Cl = 6

That's better.

Ok so we have 12.39g of P so we have 0.4 moles of it

We then have 52.54g of Cl so we have 0.74 moles of it

For every P we need 1.5 Cl so we have an excess of Cl