Question

When 21.44 moles of Si react with 17.62 moles of N, how many moles of Si³N⁴ are formed?

Answer 1

According to chemical equation

$$3 Si + 2 N_2 \to Si_3N_4$$

1) Number of moles of Si₃N₄ produced 

$$21.44\frac{1}{3}=7.15\ mol$$

2) Number of moles of Si₃N₄ produced 

$$17.62\frac{1}{2}=8.81\ mol$$

So, Si produce less number of product (Si₃N₄) so it is limiting reactant, it controls the amount of product. Or it determine the amount of product produce in a chemical reaction. So, No of moles of Si₃N₄ is 7.15 mol