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Unformatted text preview: g point becomes lower and lower. Also, super cooling introduces an ambiguity in the freezing point and should be minimized using through stirring. Materials:
· Beaker of ice water
Beaker of warm water
25 mL Test Tube
· Page 3 of 9 tbutyl alcohol
Ethylene glycol Chemistry 52 Procedure: Freezing Point Depression for tButanol: 1. Fill a large test tube approximately ¼ way with tbutanol. 2. Place the test tube, and a thermometer into the water bath so that the level of the tbutanol in the test tube is below the level of the water in the beaker. Make sure you can still read the thermometer. Cover the top of the tube with a small piece of parafilm 3. Continue heating the test tube until all its content melts. 4. Remove the water bath and allow the test tube to cool in air. 5. Record the temperature of the test tube every 30 seconds while gently agitating the contents with the thermometer. 6. Continue to record the temperature for 15 minutes, even after the tbutanol solidifies. You will have to continually cool the water bath with ice in order to freeze the sample. 7. Repeat steps 26 to obtain data for a second trial. 8. Consult the instructor to determine if the trials are successful, or if you should perform a third trial. 9. Once the trials are completed, melt the contents of the test tube and discard into waste container in the hood Freezing Point Depression of Other Solutions: 1. Similar to the directions above, determine the freezing point of the other solutions (0.5 m ethylene glycol, 1 m ethylene glycol and 0.5 m benzoic acid). 2. Place all used solu...
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