To determine the effect of changes in temperature and pressure on the position of equilibrium for the given reaction:
[tex]\[ 3 H_2(g) + N_2(g) \rightarrow 2 NH_3(g), \quad \Delta H = -92.5 \, \text{kJ} \][/tex]
we need to consider the principles of Le Chatelier's principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
### Effect of Increase in Temperature
In this reaction, [tex]\(\Delta H = -92.5 \, \text{kJ}\)[/tex], which indicates that the reaction is exothermic (releases heat). According to Le Chatelier's principle:
- For an exothermic reaction, increasing the temperature adds more heat to the system.
- The system will attempt to counteract this by absorbing the added heat, thus favoring the endothermic direction (the reverse reaction in this case).
Conclusion: Increasing the temperature will shift the equilibrium to the left, towards the reactants.
### Effect of Increase in Pressure
To determine the effect of pressure on the equilibrium, we count the moles of gaseous substances on each side of the balanced equation:
- Reactants: [tex]\(3 \, \text{moles of H}_2(g) + 1 \, \text{mole of N}_2(g) = 4 \, \text{moles of gas}\)[/tex]
- Products: [tex]\(2 \, \text{moles of NH}_3(g) = 2 \, \text{moles of gas}\)[/tex]
According to Le Chatelier's principle:
- Increasing the pressure favors the side of the equilibrium with fewer moles of gas, as the system seeks to reduce the increased pressure by decreasing the number of gas molecules.
- In this reaction, the product side (NH[tex]\(_3\)[/tex]) has fewer moles of gas compared to the reactant side.
Conclusion: Increasing the pressure will shift the equilibrium to the right, towards the products.
### Summary
- Effect of Increase in Temperature: Shifts the equilibrium to the left (towards the reactants).
- Effect of Increase in Pressure: Shifts the equilibrium to the right (towards the products).
