The following equilibrium is set up in a sealed reaction vessel - HSC - SSCE Chemistry - Question 10 - 2013 - Paper 1
Question 10
The following equilibrium is set up in a sealed reaction vessel.
$$ N_2O_4(g) \rightleftharpoons 2NO_2(g) $$
$\Delta H = +54.8 \text{ kJ mol}^{-1}$
Which of the f... show full transcript
Worked Solution & Example Answer:The following equilibrium is set up in a sealed reaction vessel - HSC - SSCE Chemistry - Question 10 - 2013 - Paper 1
Step 1
Identify Factors that Affect Equilibrium
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Answer
According to Le Chatelier's principle, if a system at equilibrium is subjected to a change, the equilibrium will shift to counteract that change. Therefore, any change in concentration, temperature, or pressure can affect the yield of nitrogen dioxide.
Step 2
Effect of Temperature
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Answer
Since the reaction is endothermic (positive ΔH), increasing the temperature will favor the production of the products (NO2), thus increasing its yield.
Step 3
Effect of Pressure
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Answer
Increasing the pressure in the reaction vessel will shift the equilibrium towards the side with fewer moles of gas. In this case, the left side has 1 mole of N2O4 while the right side has 2 moles of NO2, meaning increasing the pressure will NOT increase the yield of NO2.
Step 4
Effect of Concentration
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Answer
Increasing the concentration of the reactant N2O4 will shift the equilibrium towards the production of NO2, thereby increasing its yield.
Step 5
Conclusion
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Answer
Considering these factors, the most effective change to INCREASE the yield of nitrogen dioxide would be to increase the temperature and/or increase the concentration of N2O4.
