Principle Laboratory Co(H2O)62+(aq) + 4 Cl-(aq) CoCl42-(aq) + 6 H2O(g) Analysis: Laboratory ¬– LeChatelier’s Principle, the objective of the lab is to better, our understanding of LeChatelier’s Principle and to actually the see the shifts take place with different stressors on the system. Procedure list of materials include: . 1 M AgNO3, CoCl2, hot water bath, ice water bath, timer, and a test tube holder. Data/observations:
The color of the Cobalt Chloride by itself was a blue, after adding the silver nitrate the color of the solution changed to Pink, after heating the solution in the hot water bath for 30 seconds it changed to a purple color, after adding the sodium chloride the color changed to dark blue, and placing the test tube in the ice bath made the solution change to a pink color. After reheating the test tube in the hot water bath, the solution turned to a bluish color. Conclusion:
The following equilibrium is observed: The Co(H2O)62+ solution is pink, and the CoCl42- solution is blue. This reaction is endothermic as written, so adding heat causes the equilibrium constant to shift to the right. This, correspondingly, makes the solution blue. When the AgNO3 is added, Cl- is removed from solution. This shifts the equation back to the left, and the solution turns pink again. When HCl is added, there is more Cl- in solution, so the equilibrium is shifted to the right, and the solution turns blue.
All of the above effects are variations of LeChatelier’s principle. The precipitate that formed was AgCl, which removed Chloride from the equilibrium causing a shift to the right. The stress that was not used during the lab was the addition of pressure to the system, we did not use this because there was no need to, and we were working with test tubes so it was open to the surroundings. K= [CoCl4 ] [Co(H2O)6 ][Cl]4