Solubility Lab Report

Constructing a Solubility Curve

Georgie Dorfman, Ben Cohen, and Charlie Dorfman

7/1/13

Dr. Forman

Abstract:

My group and I worked hard to collect experimental data to construct a solubility curve for succinic acid. We needed three different temperatures (45'C, 55'C, and 65'C) to work with and record. We got many different results. As the temperature raised, so did the solubility of succinic acid. This lab was a easier than the other labs because we understood what we were doing and didn't make any mistakes. My group worked well together and we did not run into any conflicts or errors.

Significance of lab:

After preforming the solubility curve for succinic acid, I was able to understand that as water temperature increases, so does the solubility of a solute. After we aggregated our data I realized our mistake that as temperature rises, solubility never decreases. After preforming this experiment, I have a better understanding of how to test for solubility, and can use this knowledge and test the solubility of other solutes in specific temperatures.

Procedure: 

1. Prepare a warm- water bath by adding 300mL of water to a 400mL beaker.

2. Heat the beaker at 45'C.

3. Maintain this temperature by monitoring it with a thermometer and by removing the beaker from the hotplate and putting it back on the hotplate. 

4. Put 4g - 5g succinic acid in the test tube.

5. Add 20mL of distilled water to the test tube.

6. Place test tube in warm water bath.

7. For 7 minutes swirl vigorously with a glass stirring rod ever 30 seconds.

8. After 7 minutes, carefully decant the clear liquid from the test tube into a separate test tube

9. Pour the water from the beaker into the sink.

10. Prepare an ice bath by filling a 400 mL beaker with water and ice.

11. Put the test tube with the clear liquid in the ice bath for 2 minutes.

12. Stir the tube in the ice bath.

13. After 2 minutes, take the test tube out of the ice bath and let it sit at room temperature for 5 minutes.

14. Measure the height of the crystals collected in millimeters.

15. Record your observations.

16. Repeat this process of succinic acid for the 55'C observation and the 65'C observation.

17. Rise all the materials.

18. Wash your hands.

Our results:

We had successfully solidified sussinic acid in different temperatures. We did not make any mistakes. We already knew that as the temperature rises, so does the solubility of a material, but we also discovered that when the temperature rose from 55'C to 65'C, the solubility of succinic acid dropped. Usually when temperature increases, the solubility increases. The solubility of sussinic acid decreased instead of increasing at 65'C because we added more water to test for the solubility of 55'C. We could have accidentally added more than 20mL of distilled water. 

The Class's results:

The class had a variation in results. When the solution was heated to 45'C, many groups got about 15 mm. When the solution was heated to 55'C, there was a large variation in results.  When the temperature was heated to 65'C, two groups had a decrease in the solubility, and the rest had an increase.

Data Analysis:

1. For 45°C, the average was 14.1 mm. For 55°C, the average was 101.2 mm. For 65°C, the average was 102.8 mm. The results from the class varied due to the slight difference in temperatures of water.

2. The mean crystal height in milliliters vs the water temperature or my group:

Questions:

1. It is useful to do more than one trial at each temperature because the results could be different due to the small temperature changes, the slight difference in time mixing the solution, and the amount of time that the solution is left to sit (in hot water, ice water, and in room temperature). 

2. Since succinic acid is a solid solute and not a gas, we knew that when the temperature of the water rose, the solubility of the succinic acid should have increased.

3. Yes, because by cooling the solution in an ice bath and allowing it to sit in room temperature for five minutes, it recrystallized all of the succinic acid that originally dissolved in the heated water. 

4. Yes, because all of the groups in our class recorded their data. The curve was not good enough to make useful predictions about succinic acid solubility because we only experimented with 3 different temperatures. If we experimented with more temperatures and the pattern continued, then the curve would be more reliable.

5. The difficult factor of this experiment was the many factors that could easily change each group's results like the wrong measurements of temperatures, too much or too little succinic acid or time being heated and cooled.

6. Another procedure would be to take a substance and fill it with water at a certain temperature and then, we would wait for the water to cool instead of putting it in an ice bath.