Given the following reaction, what will cause no impact on the equilibrium if the forward reaction is endothermic?
[tex]2 PbS(s)+3 O_2(g)+C(s) \rightleftharpoons 2 Pb(s)+CO_2(g)+2 SO_2(g)[/tex]
A. adding C
B. adding Pb
C. applying pressure
D. applying heat
Answer (1)
Adding C or Pb (solids) does not affect equilibrium.
Applying pressure has no effect because the number of gas moles is the same on both sides.
Applying heat shifts the equilibrium to the right (endothermic reaction).
Therefore, applying pressure will cause no impact on the equilibrium. a ppl y in g p ress u re
Explanation
Analyzing the Reaction We are given the reaction: 2 P b S ( s ) + 3 O 2 ( g ) + C ( s ) ⇌ 2 P b ( s ) + C O 2 ( g ) + 2 S O 2 ( g ) . The forward reaction is endothermic, meaning it absorbs heat. We need to determine which of the given actions will not shift the equilibrium. Let's analyze each option.
Effect of Adding C Adding C: Carbon (C) is a solid. Adding or removing a solid does not change its concentration in the reaction, so adding C will have no effect on the equilibrium.
Effect of Adding Pb Adding Pb: Lead (Pb) is also a solid. Similar to carbon, adding or removing a solid does not change its concentration in the reaction, so adding Pb will have no effect on the equilibrium.
Effect of Applying Pressure Applying Pressure: To determine the effect of pressure, we need to compare the number of moles of gaseous reactants and products. On the reactant side, we have 3 moles of O 2 ( g ) . On the product side, we have 1 mole of C O 2 ( g ) and 2 moles of S O 2 ( g ) , for a total of 3 moles of gas. Since the number of moles of gas is the same on both sides of the equation, changing the pressure will not shift the equilibrium.
Effect of Applying Heat Applying Heat: The forward reaction is endothermic, meaning it consumes heat. If we add heat to the system, the equilibrium will shift to the right (towards the products) to consume the added heat. Therefore, adding heat will affect the equilibrium.
Final Answer Conclusion: Adding C, adding Pb, and applying pressure will not impact the equilibrium. However, the question asks for only one answer. Since adding C and adding Pb both have no effect, and the problem is likely testing Le Chatelier's principle regarding pressure changes, the best answer is applying pressure.
Examples
Consider an industrial process where lead is produced. Understanding Le Chatelier's principle helps control the reaction to maximize lead output. For example, knowing that adding more solid reactants like carbon won't shift the equilibrium allows focusing on other factors like temperature and pressure to optimize the process. This ensures efficient use of resources and higher yields, directly impacting profitability and reducing waste in the production of lead.
