Researcher

Samantha Gaines with Lizzie Clark

Objective

To calculate the solubility of trans-cinnamic acid in 1-pentanol by density method. The additivity of volumes is an assumption and the density of the solid is obtained from ChemSpider.

Materials

electronic balance
hot water bath
room temperature water bath
25 mL volumetric flask
beaker
pipette
microspatula
filter paper
trans-cinnamic acid
1-pentanol

‍Procedure

Weigh pure 1-pentanol solvent in 25 mL volumetric flask at room temperature. Record mass and volume. Decant solution from volumetric flask into 100 mL beaker. Add cinnamic acid until until it no longer dissolves into the solution at room temperature. Heat the solution in a hot water bath at about 40 C until cinnamic acid is dissolved. Alternate between adding cinnamic acid and heating solution in water bath until cinnamic acid does not dissolve into the heated solution. This is a saturated solution. Place beaker in a room temperature water bath and let cool to room temperature. Precipitate should form as solution cools. When completely cooled, pipette 25 mL of supernatent into volumetric flask. Weigh on electronic balance at room temperature. Record mass and volume. Calculate density of butanol and density of butanol solution saturated with cinnamic acid. Enter all data into "results" spreadsheet.

Results

Measured solubility of trans-cinnamic acid in 1-pentanol.

Dicussion

The observed density of 1-pentanol was 0.812636 g/mL. The observed density of 1-pentanol saturated with trans-cinnamic acid was 0.844580 g/mL. From this the concentration of trans-cinnamic acid in the saturated solution was calculated to be 0.61942166302306 M. The predicted solubility of trans-cinnamic acid in 1-pentanol is 1.006 M. However, the solubility of 1-pentanol should be lower than that of 1-butanol because solubility is typically inversely correlated with the number of carbons in the molecule, and 1-pentanol has 5 carbons where 1-butanol only has 4 carbons. Since the measured value for 1-butanol is .714 M this measurement for 1-pentanol is expected.

Conclusion

The measured solublity of trans-cinnamic acid in 1-pentanol was approximately 0.6194 M.

Log

2011-10-31

9:52 - Room temperature measured at 20 C.
9:53 - Weight of empty 25 mL flask taken with electronic balance measured to be 20.2519 g. Tared balance.
9:55 - Pipetted 25 mL of pentanol into 25 mL volumetric flask.
9:59 - Measured weight of pentanol in flask with tared balance. Pentanol weighed 20.3159 g.
10:19 - Transferred pentanol from volumetric flask to 100 mL beaker and added approximately 5 mL excess pentanol.
10:21 - Began adding cinnamic acid to about 30 mL of pentanol with microspatula.
10:24 - Put beaker in water bath at 40.5 C for 5 minutes.
10:30 - Continued adding cinnamic acid.
11:12 - Put beaker in water bath at 40.0 C for 3 minutes.
11:16 - Continued adding cinnamic acid.
11:20 - Put beaker in water bath at 40.0 C for 6 minutes.
11:28 - Continued adding cinnamic acid.
11:30 - Put beaker in water bath at 40.0 C for 2 minutes.
11:33 - Continued adding cinnamic acid.
11:34 - Put beaker in water bath at 40.5 C for 2 minutes.
11:37 - Continued adding cinnamic acid.
11:38 - Put beaker in water bath at 41.9 C for 3 minutes.
11:41 - Continued adding cinnamic acid.
11:42 - Put beaker in water bath at 44.0 C for 4 minutes.
11:48 - Parafilmed beaker and placed in 19 C water bath.
12:03 - Removed beaker from water bath and added cinnamic acid.
12:04 - Put beaker in water bath at 51.0 C for 3 minutes.
12:08 - Continued adding cinnamic acid.
12:09 - Put beaker in water bath at 51.0 C for 2 minutes.
12:11 - Continued adding cinnamic acid.
12:12 - Put beaker in water bath at 51.0 C for 1 minute.
12:14 - Continued adding cinnamic acid.
12:15 - Put beaker in water bath at 52.0 C for 2 minutes.
12:17 - Parafilmed beaker and put in water bath at 20.0 C.
12:24 - Observed crystals forming.
13:30 - Filtered solution into another 100 mL beaker.
13:51 - Weight of empty 25 mL volumetric flask taken with electronic balance measured to be 20.2599 g. Tared balance.
13:52 - Pipetted 25 mL of supernatant from beaker into flask.
13:57 - Weight of flask and supernatant taken with tared balance. Supernatant weighed 21.1145 g.