Question 1: Define Le Chatelier's Principle in your own words.

Answer: Le Chatelier's Principle states that if a system at equilibrium is disturbed by a change in concentration, temperature, or pressure, the system adjusts to partially counteract the effect of the disturbance and restore a new equilibrium.

Question 2: Describe how increasing the temperature affects the position of equilibrium in an endothermic reaction.

Answer: Increasing the temperature shifts the equilibrium towards the endothermic reactants or products, depending on the reaction, to absorb the added heat, favouring the endothermic direction.

Question 3: Explain why increasing pressure favours the side with fewer moles of gas in a gaseous equilibrium.

Answer: Increasing pressure causes the equilibrium to shift towards the side with fewer moles of gas to reduce the pressure and restore balance.

Question 1: Given the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g). If the initial concentrations are [N₂] = 0.5 mol/L, [H₂] = 1.5 mol/L, and [NH₃] = 0.2 mol/L, calculate the reaction quotient (Q).

Answer: Q = [NH₃]² / ([N₂] × [H₂]³) = (0.2)² / (0.5 × 1.5³) = 0.04 / (0.5 × 3.375) = 0.04 / 1.6875 ≈ 0.0237 mol²/L²

Question 2: If the equilibrium constant (Kₑq) for the above reaction at a certain temperature is 0.5, determine whether the reaction will proceed forward or reverse to reach equilibrium.

Answer: Since Q (0.0237) < Kₑq (0.5), the reaction will proceed forward to produce more NH₃ to reach equilibrium.

Question 1: Describe an experiment to investigate the effect of temperature on the position of equilibrium in the Haber process.

Answer: The experiment involves setting up a sealed container with the nitrogen, hydrogen, and iron catalyst. The reaction is carried out at different temperatures (e.g., 400°C, 500°C, 600°C). The concentrations of ammonia produced are measured at each temperature. Safety precautions include handling gases carefully, using appropriate pressure vessels, and wearing protective equipment. Data are analysed to observe how increased temperature shifts the equilibrium and affects ammonia yield.

Question 2: Identify two variables that should be controlled in an experiment investigating the effect of pressure on the equilibrium of the same reaction.

Answer: Variables to control include temperature and the initial concentrations of nitrogen and hydrogen gases.

Question 1: A study measured the amount of ammonia produced at different pressures, with results showing higher ammonia yield at higher pressures. Explain how Le Chatelier's Principle accounts for this observation.

Answer: According to Le Chatelier's Principle, increasing pressure shifts the equilibrium towards the side with fewer moles of gas. In the Haber process, fewer moles of gas are on the ammonia side, so higher pressure favours ammonia formation, increasing yield.

Question 1: A reaction at equilibrium is exothermic. Predict and explain what happens to the equilibrium position if the temperature is decreased.

Answer: Decreasing temperature shifts the equilibrium towards the exothermic side to produce more heat, thus favouring the formation of products in an exothermic reaction.

Question 2: A chemical industry produces sulphur dioxide (SO₂) and oxygen (O₂). If a reaction involving these gases is shifted by increasing the pressure, what is the likely effect on the amount of sulphur trioxide (SO₃) produced, assuming the reaction is: 2SO₂ + O₂ ⇌ 2SO₃.

Answer: Increasing pressure shifts the equilibrium towards the side with fewer moles of gas, which in this case is the side producing SO₃. Therefore, more SO₃ is produced.

Question 1: Explain how the Haber process uses Le Chatelier's Principle to optimise ammonia production.

Answer: The Haber process adjusts temperature, pressure, and catalysts to shift the equilibrium towards ammonia formation. Increasing pressure favours ammonia, which has fewer moles of gas, and a suitable temperature is used to balance reaction rate and yield, demonstrating practical application of Le Chatelier's Principle.