لخّصلي

Part A: Miscibility of Liquids

1. Examine the test tubes provided. Record in Table 1 whether the liquids are ‘miscible’ or ‘immiscible’.
   Part B: Solubility of Solutes


2. Examine the three test tubes containing benzoic acid placed in water, ethanol, and toluene. Record your observations in Table 2.


3. Examine the three test tubes containing ammonium chloride in water, ethanol and cyclohexane. Record your observations in Table 2.


4. Examine the three test tubes containing glycerol in water, ethanol and cyclohexane. Record your observations in Table 2.
   Part C: Making a Supersaturated Solution


5. Measure 4.0 mL of deionized water in a 10 mL graduated cylinder.


6. Collect your solute.
   a. Place your 50 mL beaker on the balance.
   b. Press the “0/T” button. The balance should read: 0.00 g.
   c. Add sodium acetate until you have 2.5 g.


7. Add the water from the graduated cylinder to the beaker containing the solid.


8. Insert a thermometer into the beaker.


9. Turn on your hot plate. Set it for “5”.


10. Place the solution on the hot plate and stir it occasionally as it heats.


11. Carefully remove the beaker (with the thermometer) from the hot plate when it reaches 60oC. DO NOT OVERHEAT.


12. Gently swirl the beaker until all of the salt dissolves.


13. Put about 200 mL of ice in a 400 mL beaker.


14. Place the beaker in the ice. The solution is supersaturated if no crystals appear as the solution is cooled. Do not remove the thermometer.


15. Once the temperature reaches 15°C, remove the beaker from the ice bath and gently put it on the bench top.


16. Remove the thermometer, look down into the beaker, and add a single crystal (seed crystal) of sodium acetate.


17. Observe what happens and record detailed observations in Table 3.
    Part D: Effect of Temperature on the Solubility of a Solid in a Liquid


18. Prepare a hot water bath by putting 200 mL of tap water in a 400 mL beaker and placing it on a hot plate set for 6.


19. Place a full pipette (approx. 3 mL) of 0.1 M lead (II) nitrate, Pb(NO3)2(aq), solution into a medium, clean test tube.


20. Place a full pipette (approx. 3 mL) of 0.5 M sodium chloride, NaCl(aq), solution into the same test tube.


21. Observe for 5 minutes, stirring occasionally, and record your observations in Table 4. Does a precipitate form?


22. Place the test tube in the hot water bath. Heat for about ten minutes. You may wish to swirl the test tube from time to time as it heats. Observe as it warms.


23. Record your observations in Table 4. (hint: Does heat affect the precipitate?)


24. Discard the contents of the test tube into a container labelled “waste” in a fume hood.


25. Wash your glassware, return it to the cabinet, and clean up your workspace.


26. Complete and submit your report.