Consider the reaction: [Cu(H2O)4]2+(aq) + 4 Cl-(aq) ⇌ [CuCl4]2-(aq) + 4 H2O(l) ΔH = ____ Prepare an — Chemical Equilibrium and Le Chatelier's Principle Chemistry Question
Problem Context
Consider the reaction:
[Cu(H2O)4]2+(aq) + 4 Cl-(aq) ⇌ [CuCl4]2-(aq) + 4 H2O(l) ΔH = ____
Prepare an initial [Cu(H2O)4]2+ / [CuCl4]2- equilibrium mixture by dissolving sodium chloride in 0.3 M copper(II) nitrate solution until you observe a color change.
Devise and carry out experimental procedures to
1) determine the sign of ΔH for this reaction, and
2) identify Solution A and Solution B as containing either KCl or AgNO3 based on their effect on this equilibrium system.
Give a brief description of your experimental plan.
Record your data and observations. Explain each change in color that you observed, in terms of a shift in the equilibrium position of this system.
Model Answer
a) When heated, the solution becomes greener in color, indicating a shift in the equilibrium position of the system toward the right.
b) When Solution A is added, the system becomes bluer in color, indicating a shift in equilibrium position toward the left.
c) When Solution B is added, the system becomes greener in color, indicating a shift in equilibrium position toward the right.
What is the color of each species in this equilibrium system?
Model Answer
[Cu(H2O)4]2+(aq) is blue; Cl-(aq) is colorless; [CuCl4]2-(aq) is green; H2O(l) is colorless.
The sign of ΔH for this reaction is _____.
Model Answer
+ (positive)
a) Solution A contains ___________________________.
b) Solution B contains ___________________________.
Model Answer
a) Solution A contains AgNO3.
b) Solution B contains KCl.