Question 1: Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust itself to partially counteract the effect of the change. Explain in your own words why this principle helps predict how a chemical system responds to external changes.

Answer: Le Chatelier's Principle predicts that a system at equilibrium will shift to oppose any change imposed on it, helping to restore equilibrium.

Question 1: What is meant by 'dynamic equilibrium' in a chemical reaction?

Answer: It is a state where the forward and reverse reactions occur at the same rate, and the concentrations of reactants and products remain constant.

Question 2: Name one factor that can shift the position of equilibrium according to Le Chatelier's Principle.

Answer: Changes in concentration, temperature, or pressure

Question 1: In an equilibrium reaction, the concentration of reactant A decreases when pressure is increased. If the initial concentration of A was 0.5 mol/L and after the change it is 0.3 mol/L, what is the percentage decrease in concentration?

Answer: 40%

Question 2: A reaction has an equilibrium constant (K) of 4.0 at 25°C. If the concentration of products is 0.6 mol/L and reactants is 0.3 mol/L, verify whether the system is at equilibrium.

Answer: K = [products]/[reactants] = 0.6/0.3 = 2.0; Since 2.0 ≠ 4.0, the system is not at equilibrium.

Question 1: Describe a safe method to change the temperature of a reaction mixture in a laboratory setting when investigating Le Chatelier's Principle.

Answer: Use a water bath or controlled heating device to safely increase or decrease the temperature, avoiding direct flames.

Question 2: Identify the independent and dependent variables in an experiment where you study the effect of pressure changes on the equilibrium of a gas reaction.

Answer: Independent variable: pressure; Dependent variable: position of equilibrium (concentration of reactants/products).

Question 1: A chemist observes that adding more sulfur to a system in equilibrium with sulfur dioxide and oxygen causes the production of sulfur dioxide to decrease. Explain this observation using Le Chatelier's Principle.

Answer: Adding sulfur shifts the equilibrium to produce more sulfur, which consumes sulfur dioxide and oxygen, decreasing sulfur dioxide concentration.

Question 1: Explain how Le Chatelier's Principle is used in industrial manufacturing of ammonia via the Haber process.

Answer: In the Haber process, conditions of high pressure and moderate temperature are used to shift the equilibrium toward ammonia formation, as predicted by Le Chatelier's Principle. Adjusting these conditions optimizes yield by favoring the forward reaction.

Question 2: Which of the following changes would likely increase the yield of a product in a reversible reaction at equilibrium? A) Removing some reactant B) Increasing temperature if the reaction is exothermic C) Increasing pressure if gases are involved and the reaction produces fewer moles of gas on the product side D) Adding inert gases at constant volume.

Answer: C) Increasing pressure if gases are involved and the reaction produces fewer moles of gas on the product side