Constructing A Solubility Curve Lab

Constructing A Solubility Curve Lab

July 1, 2013

Juliet, Rio, Nora

Dr. Forman

Purpose: To collect experimental data to construct a solubility curve for succinic acid, a molecular compound.

Background/Significance: After learning about the basic rules of solubility (temperature increases raise the amount of dissolved solute in a solvent; temperature decreases lower the amount of dissolved solute in a solvent), we are able to comprehend and test the solubility for succinic acid. By doing so, we enhance our understanding of solubility and can further create a graph that portrays the various amounts of solute at different temperatures.

Abstract: My group learned many important lessons from the "Constructing a Solubility Curve Lab". Once we collected data from 3 different temperatures (45 degrees C, 55 degrees C, and 65 degrees C), we confirmed the given theory that solubility increases with temperature increases. While the processes to compel the solute to dissolve in the solvent were the same, the contrasting results led us to reach a valuable conclusion.

Procedure: 

1. Prepare a warm water bath on a hot plate with about 300 mL of water and heat it to 45 degrees C

2. Fill a test tube with 4-5g of succinic acid and add 20 mL of distilled water

3. Place the test tube in the warm water bath and stir the succinic acid solution with a glass stirring rod every 30 seconds

4. Decant the clear liquid into a separate test tube
5. Carefully pour the hot water from the beaker into the sink
6. Place the new, separate test tube in an ice bath for 2 minutes, stirring occasionally

7. Tap the side of the test tube and swirl the liquid once or twice so that the crystals settle evenly at the bottom

8. Measure the height of the crystals in millimeters
9. Discard the materials and complete the same experiment with the other 2 temperatures of a warm water bath

Results: From these experiments, our group obtained incredible results. After working very well together as a team, we observed that as the temperature increases, so does solubility, also proving true the lessons that the book portrays. With our first, lowest temperature, 45 degrees C, the solute dissolved partially in the warm water bath. Once the test tube was removed from the ice bath, we noticed that there were tiny white particles floating throughout and white solute crystals sunken at the bottom. With our second, medium temperature, 55 degrees C, the solute dissolved for the majority in the warm water bath. After the test tube was removed from the ice bath, we realized that approximately 3/4 of the test tube was filled up with crystals. With our last, warmest temperature, 65 degrees C, the solute dissolved completely in the warm water bath. Following the ice bath, we observed that the test tube was almost filled completely with crystals. After gathering all of this data, we finally concluded that increases in temperature also increase the solubility of succinic acid.

Our Group Data:

Trial	Crystal Height (mm)
1	10
2	95
3	110
Average	71.67

45'C warm water bath:

Ice bath:

45'C crystallized: 

55'C warm water bath:

55'C crystallized:

65'C warm water bath:

Class Data:

Data Analysis:

1. The mean crystal height for the data obtained by the entire class was 14.1mm for 45'C, 101.3mm for 55'C, and 102.8mm for 65'C.
2. The mean crystal height in mm verses water temperature in Celsius graph:

Questions: 

1. It is useful to collect data from more than one trial at a particular temperature because then, you are able to obtain the most accurate, specific results possible.
2. I made use of the properties of a saturated solution at different temperatures because since succinic acid is a solid and it dissolved little by little as the temperature increased, I was able to understand how temperature increases can also raise the amount of solute dissolved in a solvent.
3. All of the succinic acid that originally dissolved in the water did crystallize out of the solution because of supersaturation, causing crystals to form after the solution underwent various temperature changes.
4. We did have enough data points to make a reliable solubility curve for succinic acid. The curve was good enough to make useful predictions about succinic acid solubility at temperatures we have not yet investigated because of the patterns that we discovered.
5. There are many possible errors that could occur as a result of mishaps in the procedures that could also affect our data. If we measured the succinic acid wrong, messed up the temperature, didn't mix enough, or left the test tubes in the various baths for the wrong amounts of time, our outcomes would have been different.
6. Using my knowledge of solubility, another procedure for gathering data to construct a solubility curve is by testing the effect of pressure on solubility instead of temperature.