Solubility Lab Report

Nina Gabbay

Summer Chemistry

Dr. Forman

Group Lithium: Nina, Nicolette, Makena.

Solubility Lab Report

It's not myth, just call us Lith. 

Abstract:

 The purpose of this solubility curve lab is to understand the solubility curve and to examine the solubility of every substance. We had to test the solubility of succinic acid at three different temperatures: 45°C, 55°C, and 65°C. The process for each temperature was the same; however, our results were different because as the temperature rose, the solubility also rose. This experiment required all of our group members to be attentive in order to not make any mistakes, considering one mistake could totally change our results. 

Procedure: 

At the start of the experiment, we realized that we had to work not only with our group, but with the group next to us, because we were sharing the hot plate. We organized all our materials and constantly reminded each other to not touch the hot plate. 

We first set the hot plate to the highest setting, so that the water would heat as fast as possible. After that, we poured 300 mL of tap water into our 400 mL beaker. We put the beaker onto the hot plate and placed the thermometer into the beaker, to see when the temperature would reach 45°C. After the temperature reached about 45.8°C, we took it off and placed it on the table. 

Our group worked well together because while one of us was heating the water, someone else got the 4 grams of succinic acid. We placed the 4 grams of succinic acid into a test tube, and then poured 20 mL of distilled water into the test tube. We made sure to get the large test tubes so that all the acid and water would fit. 

We then placed the test tube into the warm-water bath and stirred the acid solution every 30 seconds, for 7 minutes in order to increase the solubility. Makena and Nicolette took turns stirring, while I timed the 7 minutes. We knew that the warm-water bath would cool, so we had to heat it up during those 7 minutes to reach 45°C again. 

After the 7 minutes, we used the beaker tongs to remove the test tube from the water. We took out the water from the test tube and put it in a new test tube, leaving the undissolved solute in the original test tube. We placed the new test tube into an iced water bath, and left it there for 2 minutes.

 We then took out the test tube and let it cool in room temperature for 5 minutes. We made sure to tap the side of each test tube to allow the crystals to settle evenly on the bottom of the tube. After 5 minutes passed, there was 20 mm of solute at the bottom of the tube.

45°C: 20 mm

We repeated this process two more times, but just changed the temperature of the water to 55°C and then 65°C. We made sure to do everything the same. But the results obviously changed after we increased the temperature. At 55°C, there was 70 mm of solute on the bottom of the tube and at 65°C, there was 95 mm of solute on the bottom of the tube. 

55°C: 70 mm

65°C: 90 mm

Results: 

Our group’s results: 

Trial	Crystal Height (mm)
45°C	20 mm
55°C	70 mm
65°C	95 mm
Average	61.6 mm

Our class's data: 

The data for each group in the class differed because of many factors. Firstly, the temperature may have been slightly different. There might have been scenarios, where someone had 47°C or 46.5°C, instead of 45°C. Also, the amount of succinic acid may have been different, ranging from 4 grams to 5 grams. Therefore, these different factors may have contributed to the different results per group. 

Our class’s averages: 

Trial	Crystal Height (mm)
45°C	14.1 mm
55°C	101.2 mm
65°C	102.8 mm

Data Analysis: 

1. The table above shows the mean crystal height obtained by our entire class. For 45°C, the average was 14.1 mm, for 55°C, the average was 101.2 mm, and for 65°C, the average was 102.8 mm. 

2. In this graph, we have represented our group's data and the class's average for each temperature. The pink represents our group and the yellow represents our class. 

Questions: 

1. It is useful to do more than one trial at a particular temperature because the results could be different due to small changes in temperature,the time mixing the solution, and the amount of time that the solution is left to sit in the hot water, the 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 was risen, the solubility of the succinic acid should have risen as well.

3. Yes, all the succinic acid that originally dissolved in the water, crystallized out of the solution because by cooling the clear solution in an ice bath after separating it from its original test tube and then allowing it to sit in room temperature for five minutes, we re-crystallized all of the succinic acid that originally dissolved in the heated water. 

4. Yes, we did have enough data points to make a reliable solubility curve for succinic acid because all of the groups in our class recorded their data. However, the curve was not good enough to make useful predictions about succinic acid solubility at temperatures that we have not yet investigated because we only experimented with 3 different temperatures. If we experimented with more temperatures, our graph would help us make useful predictions. 

5. The difficult factor of this experiment was the many factors that could change each group's results.  Wrong measurements of temperatures, too much or too little succinic acid, dirty tools, and too much or too little time being heated and cooled are all factors that would lead to errors and inaccurate data.

6. A different procedure for gathering data to construct a solubility curve would be to take a substance and fill it with water at a certain temperature. Then, we would wait for the water to become a saturated solution and then change the temperatures to get different results. 

Significance of lab: 

This lab made me realize the important of working with your group members. We all had to know what was going on and stay concentrated, in order to not make errors which would change our results. At the same time, we each had to take on a certain responsibility during the experiment, so that we could properly proceed with each step. This lab not only required attentiveness and working with your team members, but also patience. You needed to follow the directions and wait how ever long was needed, in order to get results.