Equilibrium unit test
A test on this unit alone, marked as a percentage and a letter grade — for the test your class is actually sitting, rather than for May. Answer everything, then submit once: seeing the answer to question 3 before attempting question 4 makes the final percentage meaningless.
Dynamic equilibrium
Effect of volume change
Q vs K reasoning on a graph
Relating K for reversed and scaled reactions
Magnitude of K
Equilibrium constant K
Le Châtelier's principle
Small-x approximation
Common ion effect
ICE table
Kc and Kp relationship
Reaction quotient Q
Short answer 1. Define or explain: Solubility product Ksp
3 ptsShort answer 2. Define or explain: pH effect on solubility
3 ptsShort answer 3. Define or explain: Effect of temperature on K
3 ptsShort answer 4. Define or explain: Effect of a catalyst on equilibrium
3 ptsFree response
4 ptsA student investigates whether a reaction is exothermic or endothermic by observing an equilibrium system at two temperatures: Co(H₂O)₆²⁺(aq) + 4 Cl⁻(aq) ⇌ CoCl₄²⁻(aq) + 6 H₂O(l) pink blue When the solution is heated, it turns blue; when cooled, it turns pink.
(a) Determine whether the forward reaction is endothermic or exothermic, and justify your answer.
(b) Predict the effect on the color of the solution of adding concentrated HCl, and justify your prediction.
(c) Predict the effect on the color of adding AgNO₃ solution, which precipitates chloride ion, and justify your prediction.
(d) Explain why adding water to the solution shifts the equilibrium toward pink.