Lab 1: Colligative Properties & Osmotic Pressure Essay Example
Ankur Sindhu Sep 20, 2011 CHEM 182-DL1
Prof.: Dr. Nidhal Marashi
Lab 1: Colligative Properties & Osmotic Pressure
Purpose: The purpose of this laboratory was to gain an understanding of the differences between the freezing points of pure solvent to that of a solvent in a solution with a nonvolatile solute, and to compare the two.
Secondly, osmosis was to be observed to gain a proper understanding of how the principal of dialysis functions.
Procedure:
1. Make a water bath assembly by doing the following: a. Half-fill the 100-mL beaker with cool tap water. b. Place crushed ice in the beaker so the water level is just below the top of the a. beaker. The water level should not be higher than the length of the test tube. b. Sprinkle a little salt into the ice water. Mix well. 1. Half-fill the test tube with distilled water. Set the tube into the 24-well plate. (The well plate will function as a test tube holder.) 2. Insert the thermometer into the test tube and take readings every 30 seconds until the readings remain constant, then record the temperature of the distilled water. 3. Place the test tube in the beaker‘s ice water bath and set your stopwatch at zero. 4. Carefully stir the water in the test tube with the thermometer and record the temperature of the water at 30-second intervals. You should see the temperature of the water rapidly decrease to from -1C to -3C then rise to 0C. At that time the readings should remain constant before again decreasing. This is super cooling. 5. Caution: Do NOT let the water in the test tube freeze completely or the thermometer may break. 6. Once five consecutive readings have been made at a constant temperature, remove the test tube from the bath and empty it into a sink. 7. Refill half of the test tube with room temperature distilled water (at least 10C) and add 1/8 teaspoon of salt to the distilled water in the test tube. Mix well
Prof.: Dr. Nidhal Marashi
Lab 1: Colligative Properties & Osmotic Pressure
Purpose: The purpose of this laboratory was to gain an understanding of the differences between the freezing points of pure solvent to that of a solvent in a solution with a nonvolatile solute, and to compare the two.
Secondly, osmosis was to be observed to gain a proper understanding of how the principal of dialysis functions.
Procedure:
1. Make a water bath assembly by doing the following: a. Half-fill the 100-mL beaker with cool tap water. b. Place crushed ice in the beaker so the water level is just below the top of the a. beaker. The water level should not be higher than the length of the test tube. b. Sprinkle a little salt into the ice water. Mix well. 1. Half-fill the test tube with distilled water. Set the tube into the 24-well plate. (The well plate will function as a test tube holder.) 2. Insert the thermometer into the test tube and take readings every 30 seconds until the readings remain constant, then record the temperature of the distilled water. 3. Place the test tube in the beaker‘s ice water bath and set your stopwatch at zero. 4. Carefully stir the water in the test tube with the thermometer and record the temperature of the water at 30-second intervals. You should see the temperature of the water rapidly decrease to from -1C to -3C then rise to 0C. At that time the readings should remain constant before again decreasing. This is super cooling. 5. Caution: Do NOT let the water in the test tube freeze completely or the thermometer may break. 6. Once five consecutive readings have been made at a constant temperature, remove the test tube from the bath and empty it into a sink. 7. Refill half of the test tube with room temperature distilled water (at least 10C) and add 1/8 teaspoon of salt to the distilled water in the test tube. Mix well