Chemistry 0620 · IGCSE · Reversible reactions and equilibrium
Reversible reactions and equilibrium — practice question
Dinitrogen tetroxide, N₂O₄, breaks down to nitrogen dioxide, NO₂. This is a reversible reaction.
$\text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g)$
Fig. 4.1 shows a sealed gas syringe that contains a mixture of dinitrogen tetroxide and nitrogen dioxide. The gas syringe is sealed. The mixture reaches equilibrium and the gases are a pale brown.
(a)[2]
Describe a reversible reaction at equilibrium by referring to the forward and reverse reaction rates and the concentrations of the reactants and products.
(b)[1]
Explain in particle terms why the mixture immediately becomes a darker brown.
(c)[1]
State what can be deduced about the forward reaction from this information.
(d(i))[4]
Complete Table 4.1 using only the words increases, decreases or no change.
(d(ii))[2]
Deduce the oxidation number of sulfur in S and in SO₃.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Forward and backward reaction rates are the same” …