Exp200

=Researcher=
 * John Hunyara**

=Objective= To determine the solubility of trans-cinnamic acid in methanol by the density method.

= = =Results= [|Google Spreadsheet - Exp200 - 1] Molarity was determined for the solution of methanol and cinnamic acid in each of the 3 volumetric flasks: 5 mL flask: 1.81 M 2 mL flask: 1.67 M 1 mL flask: -0.02 M (error)

= = =Discussion= The range of molarity for this experiment was 1.67-1.81 M. The value recorded for the 1 mL flask produced a negative answer, implying a mass measurement error. Past [|results] gave a range of 1.3-1.52 M. The values measured for this experiment were slightly outside the expected range from past experiments. A molarity of 1.431 M is the accepted value for the solubility of cinnamic acid in methanol. Contaminants or measurement error on the weigh scale may have caused values out of the range.

= = =Conclusion= Although densities were recorded, the values for the 5 mL flask and the 2 mL flask were slightly above the accepted molarity of 1.431 M. The value for the 1 mL flask was calculated through an error and is not even logical.

= = =Log= 14:05
 * 2011-01-25**

14:06 - Water bath turned on to 40 C. 14:11 - 5.91 grams of trans-cinnamic acid were measured into a 20 mL tube. Methanol was added to fill up the majority of the tube, leaving some space at the top. 14:48 - Temperature in the bath was at 42 C. Solution was placed in bath at this time. 14:58 - Dry volumetric flasks of 5 mL, 2 mL, and 1 mL were used to measure densities of pure methanol. 15:45 - Another water bath was set up. Temperature was at 23 C. 16:10 - Bath temperature was at 40 C. Tube was removed. 16:12 - Supernatant was decanted and placed in another 20 mL tube. At this time the new tube was placed in the 23 C bath. Crystallization occurred. 16:35 - Tube was removed from 23 C bath and supernatant was again removed. 16:38 - Dry volumetric flasks of 5 mL, 2 mL, and 1 mL were used to measure densities of the methanol/cinnamic acid solution.