A(g) ⇌ B(g) + C(g) Kc = 2.5 at 350 K A rigid container of constant volume initially…
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
A(g) ⇌ B(g) + C(g) Kc = 2.5 at 350 K
A rigid container of constant volume initially contains the mixture shown in Diagram I:
• 24 A molecules
• 4 B molecules
• 4 C molecules
Three additional diagrams (E1, E2, E3), each portraying 32 total gas particles of the same three species, are proposed as possible states of the system after it has reached equilibrium at 350 K:
• E1: 16 A, 8 B, 8 C
• E2: 12 A, 10 B, 10 C
• E3: 8 A, 12 B, 12 C
(a) Using the initial particle counts from Diagram I, calculate the value of the reaction quotient Qc. Show all steps.
(b) Based on the comparison of Qc with Kc, predict the direction in which the reaction will proceed as it moves toward equilibrium. Explain your reasoning.
(c) Construct an ICE (Initial–Change–Equilibrium) table using particle counts to determine the expected whole-number counts of A, B, and C at equilibrium. Provide justification for any rounding that you perform.
(d) Identify which of the three proposed diagrams (E1, E2, or E3) best represents the system at equilibrium. Support your choice with quantitative comparisons to your calculated equilibrium counts.
(e) Describe qualitatively what would happen to the equilibrium position if the volume of the container were suddenly doubled at constant temperature, and explain your reasoning in terms of Le Châtelier’s principle.