If 5 moles of p4 reacted with 22 moles cl2 according to the above reaction, determine:
a. how many moles pcl3 are produced
b. how many moles of p4 are left in excess after the reaction (if any)
c. how many moles of cl2 are left in excess after the reaction (if any)

Solution:

a) By stoichoimetry If 6 moles of gives 4 mole of , then 22 moles of will give: moles of

b) If 6 moles of reacts with one mole of , then 22 moles of will react : moles of

Moles of  left after the reaction = moles.

c) 0 Moles of , since it is present in less amount it will get completely consumed in the reaction. Hence, it is limiting reagent.

there are two significant figures.