Question

Given the reaction: 4NH3 + 3O2 → 2N2 + 6H2O. How many moles of N2 are produced when 1.0 mole of NH3 is consumed?

Answer 1

From the given balanced chemical reaction, 4NH3 + O2 ---> 2N2 + 6H2O, the ratio of the number of moles of NH3 consumed to the number of moles N2 produced is 4:2 or 2:1. Thus, for 1 mole of N2 produced, 2 moles of NH3 are consumed. 

Answer 2

Answer: 0.5 moles

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$4NH_3+3O_2\rightarrow 2N_2+6H_2O$

According to stoichiometry,

4 moles of ammonia produce = 2 moles of nitrogen

1 mole of ammonia produce =$\frac{2}{4}\times 1=0.5$ moles of nitrogen

Thus 0.5 moles of nitrogen are consumed when 1 mole of ammonia is consumed.