Question

b) [i], [ii], [iii], [iv]

b) i) Using colours and a legend, sketch a diagram of 4 molecules of ammonia inside a sealed container and another diagram of the same container after the reaction is complete. Reactants Products ii) How many molecules of each product are formed when 4 molecules of ammonia react? iii) What is the simplest ratio of molecules of reactants and products? iv) Relate your answer for question (iii) above, to the balanced chemical equation for the decomposition of 2 molecules of ammonia.

Answer 1

b)

i) NH₃ decomposes according to the following reaction

  

2NH3(g) + N2(g) + 3H2(g)

Hence, we will get N₂ and H₂ in the reaction mixture after the reaction is complete.

H-CH NEN HGH HH H— H нин HHH H— H H— H H— H- H H NEN Before reaction 4 molecules of NH3 After reaction, 2 molecules of N, and 6 molecules of H2

ii)

The number of molecules of each product formed is

$2\ {\color{Red} N_2 }$ and $6\ {\color{Blue} H_2 }$

iii)

The simplest ratio of molecules of reactants and products can be calculated by dividing their ratio with a common factor,

The ratio is

42 NH3 : N2 : H2 = 4:2:6= :5: = 2:1:3

Hence, the simplest ratio is
2 NH3:1 N2:3 H
.

iv)

The balanced equation is

2NH3(g) + N2(g) + 3H2(g)

Hence, the coefficients of the balanced reaction matches with the simplest ratio of the molecules of reactants and products,.

That is , 2 moles of NH₃ decomposes to form 1 mole of N₂ and 3 moles of H_2.