FC: Sunshine Christian BilingualSchool Mr.Jose Popoff Victor Ariel solubility curve lab report November/4/2012
1: Introduction In this lab activity we demonstrate the effect of solubility curve on hot and cold salt solution and when it begins to crystallize Goals Demonstrate how the solubility of a salt varies with temperature. Plot the solubility curve of a salt on the basis of observed data.
2: Materials ammonium chloride balance beaker, 250 mL Bunsen burner glass stirring rod graduated cylinder, 10 mL iron ring matches metric ruler ring stand test tube holder test tubes, 4 thermometer wire guaze
3: Procedure 1. prepare the materials. a) Label four test tubes as follows: 4,4.5,5 and 5.5. b) obtain 4.00 g of ammonium chloride; then add it to the test tube labeled 4. Repeat this step for 4.50 g, 5.00 g, and 5.50 g of ammonium chloride. c) Add exactly 10.0 mL of water to each test tube. d) Set up a hot water bath, using a 250 mL beaker. e) Place the four test tubes into the hot water bath. Do not let any water from the beaker get into the test tubes; it is imperative that you not change the concentrations of the solutions.
4: 2. Test the solubility versus temperature. a) When the hot water bath begins to boil, stir the solutions to help dissolved the ammonium chloride. When the solute in all four tubes has completely dissolved, turn off the burner. The bath will remain hot for some time. b) Using a test tube holder, remove test tube 5.5 from thee water bath and place it in a test tube rack. Place a thermometer into the test tube and allow the solution to cool. You may periodically stir the solution gently with the thermometer. c) Check the temperature at which crystallization occurs. (Record: 1) Double check this temperature by reheating the test tube just enough to dissolved the solute again. Recool the solution. (Record: 2) If the temperature for the first and second crystallizations differs by more than a few
5: degrees, carefully repeat the reheating and recooling process. d) Repeat Steps 2b-c for the solutions containing 5.00, 4.50, and 4.00 g of ammonium chloride. Note: A cold water bath may be needed to hasten the crystallization of the 4.00 g sample.
6: Data 1. Temperature for the first crystallization of the 5.50 g sample= 74.3 degrees 2. Temperature for the second crystallization of the 5.50 g sample= 63.4 degrees 3. Temperature for the first crystallization of the 5.00 g sample= 68.9 degrees 4. Temperatures for the second crystallization of the 5.00 g sample= 63.2 degrees 5. Temperature for the first
7: crystallization of the 4.50 g sample= 64.3 degrees 6. Temperature for the second crystallization of the 4.50 g sample= 56.4 degrees 7. Temperature for the first crystallization of the 4.00 g sample= 57.6 degrees 8. Temperature for the second crystallization of the 4.00 g sample= 21.1 degrees
8: Conclusion we conclude that the solubility of a solid dissolved in a liquid is larger when temperature is higher, but smaller when the temperature is lower.