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Part of the Contact Process for the manufacture of sulfuric acid involves the conversion of sulfur dioxide to sulfur trioxide, as shown by the equation \[ 2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) \quad \Delta H = -192 \text{ kJ mol}^{-1} \] As part of a laboratory study of this process, a container was filled with an equilibrium mixture of sulfur dioxide, sulfur trioxide and oxygen in the presence of a catalyst - VCE - SSCE Chemistry - Question 2 - 2003 - Paper 1
Question 2
![Part-of-the-Contact-Process-for-the-manufacture-of-sulfuric-acid-involves-the-conversion-of-sulfur-dioxide-to-sulfur-trioxide,-as-shown-by-the-equation--\[-2SO_2(g)-+-O_2(g)-\rightleftharpoons-2SO_3(g)-\quad-\Delta-H-=--192-\text{-kJ-mol}^{-1}-\]--As-part-of-a-laboratory-study-of-this-process,-a-container-was-filled-with-an-equilibrium-mixture-of-sulfur-dioxide,-sulfur-trioxide-and-oxygen-in-the-presence-of-a-catalyst-VCE-SSCE Chemistry-Question 2-2003-Paper 1.png](https://cdn.simplestudy.cloud/assets/backend/uploads/question/subject_1954_paper_21211_b_q2_67bdc92f.jpg)
Part of the Contact Process for the manufacture of sulfuric acid involves the conversion of sulfur dioxide to sulfur trioxide, as shown by the equation \[ 2SO_2(g) ... show full transcript
Worked Solution & Example Answer:Part of the Contact Process for the manufacture of sulfuric acid involves the conversion of sulfur dioxide to sulfur trioxide, as shown by the equation \[ 2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g) \quad \Delta H = -192 \text{ kJ mol}^{-1} \] As part of a laboratory study of this process, a container was filled with an equilibrium mixture of sulfur dioxide, sulfur trioxide and oxygen in the presence of a catalyst - VCE - SSCE Chemistry - Question 2 - 2003 - Paper 1
Step 1
What change occurred at the 10 minute point?
Answer
At the 10-minute point, the concentration of the reactants and products reached a dynamic equilibrium state. This means that the rates of the forward and reverse reactions are equal, and there are no net changes in the concentrations of the substances present.
Step 2
Step 3
Give explanations for the changes in concentration that occur in X, Y and O₂ between 10 and 20 minutes.
Answer
Between 10 and 20 minutes, the addition of O₂ shifts the equilibrium position to the right, according to Le Chatelier's principle. This results in an increase in the concentration of SO₃ (Y) as more of the reactants (SO₂ and O₂) convert into products. Conversely, the concentration of SO₂ (X) will increase as O₂ (reactant) is added, due to the initial shift in equilibrium that favors the formation of SO₃.
Step 4
Would the temperature of the mixture increase, decrease or remain the same between 10 and 20 minutes? Explain your reasoning.
Answer
The temperature of the mixture would remain the same between 10 and 20 minutes. The forward reaction is exothermic, and since the system is thermally well insulated, any heat produced will be retained. However, the equilibrium temperature would not change, as the reaction’s heat has reached a balance.