Lab Report: Constructing a Solubility Curve

LAB REPORT

Constructing a Solubility Curve

Charlie, Ben, Georgie

7/1/13

Dr. Forman

Purpose:

The purpose of this lab is to collect an experimental data to construct a solubility curve for succinic acid.

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.

Abstract:

In this experiment, my group and I worked hard to make succinic acid dissolve in water. However, to construct a solubility curve we needed three different temperatures in which we would record. These temperatures included 45'C, 55'C, and 65'C. We noticed that as the temperature raised, so did the solubility of succinic acid. Although the process for each temperature was the same, the results were very different. These different results made the experiment more interesting because it kept me guessing.

Procedure: 

• Prepare a warm- water bath by adding 300mL water to a 400mL beaker 

• Heat the beaker to 45'C
• Maintain this temperature with a thermometer, and by removing the beaker from the hotplate and putting it back on 
• Place 4g - 5g succinic acid in the test tube
• Add 20mL of distilled water to the test tube, as well
• Place test tube in warm water bath

• After every 30 seconds for 7 minutes, swirl vigorously with a glass stirring rod

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

• Pour the hot water from the beaker into the sink
• Prepare an ice bath by filling a new 400 mL beaker with water and ice

• Place the test tube containing the clear liquid in the ice bath for 2 minutes
• Stir the tube in the ice bath every now and then
• After 2 minutes, take the test tube out of the ice bath, and allow the tube to sit at room temperature for  5 minutes

• Measure the height of the crystals collected in millimeters (mm)

• Record your observations
• Repeat this process for the 55'C observation and the 65'C observation of succinic acid

• Rise all the materials
• Wash your hands

Results:

After working with my group, we had great success in solidifying sussinic acid in different temperatures. This lab was a somewhat easier task to preform than the other labs so far because we understood what we were doing and didn't make any mistakes.  In our results, we observed that it is true that as temperature raises, so does the solubility of a material, but we also found it interesting that as the temperature went from 55'C to 65'C, the solubility of succinic acid dropped. Usually when one raises the temperature, the solubility should increase as well. One explanation to why the solubility of sussinic acid dropped instead of raised at 65'C could be that we added more water in the procedure to test for the solubility of 55'C. We could have added more than 20mL of distilled water on accident. In conclusion, I think my group worked really well with each other, and now that we have been with these groups for a couple of weeks, it's much easier to work with them.

Class aggregated data:

As a class, there were a variety of of numbers on how much sussinic acid can be dissolved at a specific temperature. When the solution was heated to 45'C, many groups got an average of about 15 mm. When the solution was heated even more to 55'C, there was a huge gap in numbers. Two groups got about 145mm, and others got around 80mm of sussinic acid that can be dissolved. Finally when the temperature was heated even more to 65'C, two groups had a decrease in the solubility, and the rest of the groups had an increase of solubility as the temperature raised. The different numbers from each group results in how well the groups followed directions.

Data Analysis:

1. The mean crystal height obtained by the class for each temperature recorded is 45'C the average was 14.1 mm. For 55'C was about 101.2. And for 65'C the average was 102.8 mm.

2. The mean crystal height in milliliters versus the water temperature in degrees celsius for my group:

Questions

1. It is useful to collect data from more than one trial at a particular temperature because it gives you a more accurate number for your results when using different temperatures.

2. I made use of the different properties of a saturated solution at different temperatures because I knew that succinic acid is a solid, so when the temperature rises, so should the solubility of the solute as well.

3. Yes, all the succinic acid that originally dissolved in water crystalized out of the solution because of supersaturation. We allowed the substance to heat, then cool, and then allowed it to sit at room temperature, which re-crystalized the succinic acid.

4. Yes, the solubility curve is a reliable solubility curve for succinic acid that would be a good enough curve to make useful predictions about succinic acid solubility at temperatures i have not yet discovered because its known that as temperatures rise, so does the solubility level. And as temperatures decrease, so does the solubility  level. So if I heated the reaction to a temperature higher than 65'C, I could guess that the solubility of the acid would increase too.

5. The procedures in this investigation that could lead to errors is when you measured the amount of succinic acid to supply. This could affect my data because it would require a warmer temperature to dissolve all the solute. Another procedure that could lead to errors is making sure the temperature is exactly at what you need it to be. This could affect my data because if i am testing the solubility at 45'C, I cant have the solution be at 55'C, that would throw off my whole data.

6. Another procedure for gathering data to construct a solubility curve would be to heat a solution and allow it to cool, without putting the solution in a ice bath.