Iron Silver Equilibrium Study Guide

Experiment 4 Guide Questions for Discussion Iron-Silver Equilibrium

1. Give the balanced net ionic equation for the reaction between Fe2+ and Ag+. What is the chemical formula of the gray precipitate?
Answer:
Fe2+(aq) + Ag+ (aq) Fe3+(aq) + Ag (s) The formula of the precipitate is Ag(s). 2. Give the balanced net ionic equation for the reaction of Fe2+ with Fe(CN)63-. a. What is the chemical formula of the Prussian blue precipitate? b. How does the formation of the Prussian blue precipitate affect the reaction in (1)?
Answer:
Fe2+ + Fe(CN)63- Fe[Fe(CN)6]- a. The formula of the Prussian blue precipitate is [Fe(CN)6]-. b. The formation of the Prussian blue precipitate
This concludes that the mixture is at equilibrium and Keq cannot exceed to 100 nor it would be less than 0.01.

Copper-Ammonia Equilibrium

6. At the beginning of the reaction between Cu2+ and NH3(when only a few drops of ammonia have been added): g. What is the color of the precipitate formed? h. What is the identity of the precipitate formed? i. Explain how this precipitate formed. Provide the net ionic equation. 7. When the precipitate has dissolved upon addition of more ammonia, what is the color of the solution? What copper complex is responsible for this? 8. Provide the balanced net ionic equation for the formation of this copper complex. 9. Explain how the addition of HCl decolorized the solution. 10. Give the balanced net ionic equation for the reaction responsible for the shift in equilibrium for this system.

Answer: j. (a) a white precipitate is formed (b) caused by the formation of Cu(OH)2 (c) which is described by the equation Cu2+ + 2OH- Cu(OH)2 since ammonia is present as an aqueous solution, thus the reacts w/ the hydroxide part to yield