Conclusions and Questions:
1. Write equilibrium equations for the reversible reactions that take place in Part A and Part B.
a) FeCl3 + 3KSCN Fe(SCN)3 + 3KCl
b) FeCl3 + 3KSCN Fe(SCN)3 + 3KCl
c) FeCl3 + 3KSCN Fe(SCN)3 + 3KCl
d) K2CrO4 + 2HCl H2CrO4 + 2KCl
e) K2CrO4 + 2NaOH Na2CrO4 + 2KOH
f) K2Cr2O7 + 2HCl H2Cr2O7 + 2KCl
g) K2Cr2O7 + 2NaOH Na2Cr2O7 + 2KOH
2. Using Le Chatelier’s principle, explain how the addition of FeCl3 to the solution in test tube 2(step3) affected the equilibrium that existed in the solution. Give similar explanations for the addition of each of the other substances (step4).
The addition of FeCl3 to the equilibrium system caused an increase of the concentration of FeCl3 thus causing the rate of the forward reaction to increase.
3. Using the equailibrium equations for the reaction and Le Chatelier;s principle, explain the color change noted in part B.
The color changes in part B was due to and increase of concentration to one side of the reaction causing an increase in the stress. To relieve the stress the reaction shifted from one side to the other.