Hieu Nguyen.


To determine the solubility of (trans) - cinnamic acid in methanol by using density method. The additivity of volumes is an assumption.


Cinnamic acid was slightly dissolved in methanol at room temperature. The mixture then was placed in the temperature control bath at 25 celsius degree overnight to allow the precipitate to form. The satureated solution was removed from the precipitate and weighed using a 1 mL volumetric flask.


ONS-EXP339-Sheet 1
Using a 1 mL volumetric flask, the molarity of a methanol solution saturated with cinnamic acid was found to be 1.281 M.


Previous experiments have found the solubility of cinnamic acid in methanol to range from 1.226 - 1.52 M with a mean of 1.332. Therefore, the 1.281 M found in this experiment is precisely correct.


The density method was performed successfully showed that the solubility of (trans) - cinnamic acid in methanol at 25 Celsius degree is 1.281.



10:45 -- Weighed out 2.00 grams of cinnamic acid and added it to a clean 20 mL test tube.
10:50 -- Transferred exactly 5 mL of methanol solution to a graduated cylinder.
10:52 -- Delivered 5mL of methanol solution from graduated cylinder to the 20 mL test tube containing cinnamic acid by using funnel.
10:53 -- The test tube was capped with a screw cap, and then sealed with parafilm.
10:54 -- Shook the mixture up side down.
10:55 -- Observed that the mixture form 2 different layers, one white thick layer at the bottom and a light yellow liquid layer at the top of the test tube.
11:18 -- Took picture 1
11:19 -- Placed the test tube in the temperature control bath at 25 Celsius Degree.
11:20 -- Set the rotating magnet at level 3.


10:23 -- Weighed out an empty 1 mL volumetric flask and recorded its mass.
10:25 -- Filled the flask with exactly 1 mL of pure solvent methanol.
10:27 -- Weighed out the flask with methanol and recorded its mass.
10:29 -- Pour the methanol into the waste container and dried the flask.
10:32 -- Weighed out the empty volumetric flask again.
10:36 -- Took the test tube out of the temperature control bath.
10:39 -- Removed the screw cap from the test tube.
10:40 -- Transferred 1 mL of the solution into the 1 mL volumtric flask using a pipet.
10:43 -- Weighed out the voluemtric flask with the solution and recorded its mass.
10:47 -- Washed it using acetone.