Purpose: To observe freezing point depression and Osmotic pressure
Materials: Student Supplied – Karo Syrup, Salt, Distilled water, Vinegar, Egg, Ice, Glass, Measuring spoon
LabPaq materials: Test Tube, Thermometer, 100mL plastic beaker, 24-well plate
Procedure: Start the Osmotic Pressure procedure several days before the due date!
Freezing Point Depression
1. Place ice water in 100mL beaker, up to the 100mL mark. (not precise)
2. Add “some” salt to the ice water. This cools the water down faster. (Mythbusters proved this once. )
3. Fill the test tube about half way with distilled water and insert the thermometer.
4. Place the test tube assembly in the 24-well plate as a secure place to hold the test tube.
5. Read the thermometer, to the hundredths place, until the temperature is stable. Record in Table 1 below. Add rows to the table as needed.
6. Place the test tube assembly into the beaker of ice water.
7. Start the stop watch and take temperature readings every 30 seconds until the temperature remains constant. (Remember to read the thermometer to the hundredths place!) you might see the temperature cool rapidly to -2 or -3 then rise to 0C. That is expected. Continue to record 5 temperatures after that rise occurs.
8. Dump out the cold water and refill the test tube half way with room temperature distilled water.
9. Carefully add 1/8 teaspoon of table salt to the test tube. (The salt won’t dissolve as much in cold water, so it is best to restart with warmer water.)
10. Stir gently with the thermometer and take readings, as in #5, until the temperature is constant. Record these temperatures in Table 2 below.
11. Place the test tube assembly in the beaker of ice water.
12. Start the stop watch and take temperature readings every 30 seconds until the temperature remains constant. (Remember to read the thermometer to the hundredths place!)
You will graph this data in the Results & Discussion section.
1. Record physical...