Question

If 5 moles of P4 reacted with 22 moles Cl2 according to the above reaction, determine:
a) How many moles PCl3 are produced a)________________

b) How many moles of P4 are left in excess after the reaction (if any) b)________________

c) How many moles of Cl2 are left in excess after the reaction (if any) c)________________

Answer 1

Where is the reaction?

Answer 2

You should first write and balance the equation.
P4 + 6Cl2 - 4PCl3

Using ratio and proportion... According to our equation, 1 mol of P4 reacts with 6 of Cl2 and 1 mol of P4 as to 4 mol of PCl3

If you have 5 mol of P4, it should have reacted with 5*6/1=30 mol of Cl2
Or if you have 22 mol of Cl2, it should react with 22*1/6= 11/3 mol of P4
b) 5-11/3 = 1.33
a) 11/3
c) none, because Cl2 is the limiting reagent.