Phosgene decomposes according to the following reversible reaction
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
Phosgene decomposes according to the following reversible reaction.
COCl2(g)⇌CO(g)+Cl2(g)
The equilibrium constant has the following values:
• Kc=0.082 at 600 K
• Kc=0.19 at 700 K
(a) Determine the sign of ΔH for the forward reaction. Provide chemical reasoning based on the data.
(b) A mixture at equilibrium at 600 K is rapidly heated to 700 K, and the total volume of the container remains unchanged. Predict the direction of the net reaction as the system moves toward the new equilibrium. Justify your prediction.
(c) State which of the three species (COCl2, CO, or Cl2) will show an increase in concentration once equilibrium at 700 K is re-established. Briefly explain your reasoning.