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1. What would happen if the temperature was increased for the reaction below: N2(g) 3H2(g) (reversible reaction) 2NH3(g) The forward reaction is exothermic.
   • If the temperature is increased, then the equilibrium will shift to the left (the endothermic direction), to remove the extra heat added. This is why only a moderately high temperature (380 - 450°C) is used in the Haber process.
2. What would happen if the temperature was decreased for the reaction below: N2(g) 3H2(g) (reversible reaction) 2NH3(g) The forward reaction is exothermic.
   • If the temperature is decreased, then the equilibrium will shift to the right (the exothermic direction), to produce additional heat.
3. Does increasing the temperature of a reaction favor the endothermic or exothermic reaction?
   • Increasing the temperature always favours the endothermic reaction. Decreasing the temperature always favours the exothermic reaction
4. What does the term equilibrium mean?
   • When a reversible reaction occurs in apparatus which prevents the escape of reactants and products, equilibrium is reached when the forward and reverse reactions occur at exactly the same rate.
5. When does changing the pressure of gaseous reactions not affect the equilibrium?
   • Changes in pressure will not affect the position of equilibrium, if the number of moles of gases on both sides of the equation are equal. Remember, liquids and solids contribute nothing to the volume of the equilibrium mixture.
6. How does increasing and decreasing the pressure for gaseous reactions at equilibrium?
   • For gaseous reactions at equilibrium: - an increase in pressure causes the equilibrium position to shift towards the side with the smaller number of molecules as shown by the symbol equation for that reaction - a decrease in pressure causes the equilibrium position to shift towards the side with the larger number of molecules as shown by the symbol equation for that reaction.
7. What does the relative amounts of all the reactants and products at equilibrium depend on?
   • The relative amounts of all the reactants and products at equilibrium depend on the conditions of the reaction.
8. What happens when a system is at equilibrium and a change is made to the conditions?
   • If a system is at equilibrium and a change is made to any of the conditions, then the system responds to counteract the change.
9. What is Le Chatelier's principle used for?
   • The effects of changing conditions on a system at equilibrium can be predicted using Le Chatelier's Principle.
10. How would changing the conditions of the equation below effect the equilibrium? A(g) 2B (g) (reversible arrow) C(g) D(g) a) increasing concentration of A b) increasing the pressure of the reactants c) increasing the temperature of the reaction (the forward reaction is exothermic)
    • Changing the conditions of the equation below would have the following effects on the equilibrium: A(g) 2B (g) (reversible arrow) C(g) D(g) a) equilibrium would shift to the right to reduce the amount of A Particles b) equilibrium would shift to the right as there are fewer gas molecules in the products than in the reactants c) equilibrium would shift to the left as the reaction tries to cool itself down again
11. What happens when the concentration of one of the reactions or products in an equilibrium system is changed?
    • If the concentration of one of the reactants or products is changed, the system is no longer at equilibrium and the concentrations of all the substances will change until equilibrium is reached again.
12. What happens when the concentration of a reactant is increased in an equilibrium system?
    • If the concentration of a reactant is increased, more products will be formed until equilibrium is reached again.
13. What happens when the concentration of a reactant is decreased in an equilibrium system?
    • If the concentration of a product is decreased, more reactants will react until equilibrium is reached again.
14. What would happen if the concentration of potassium chloride is increase? Cl2(g) H2O(l) (reversible arrow) Cl-(aq) ClO-(aq) 2H (aq)
    • If potassium chloride (a source of chloride ions) is added to the equilibrium mixture, the equilibrium will shift to the left, to remove the chloride ions added.