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Solubility book (3rd Edn)
To determine the solubility of trans-cinnamic acid using the density method
Dissolve cinnamic acid and methanol in a test tube using the boiling technique in an approximately 70C water bath. Remove the test tube and pour the supernatant to another test tube and set it in a 25C water bath until a precipitate forms. Take mass of an empty 5mL volumetric flask, the same flask with 5mL of pure methanol, and the same flask with 5mL of the supernatant that formed in the second test tube.
The molarity when 5mL of the supernatant was weighed in a 5mL volumetric flask was 1.3055M.
Results of Previous Experiments
From the previous results of this experiment, the average solubility determined for cinnamic acid was 1.332M where the solubility determined in this experiment was 1.3055M. The result of this experiment showed good agreement with the average determined from 18 other experiments.
Using the density method, i was able to determine that the solubility of cinnamic acid is around 1.3055M.
11:55 - Weighed out 4.9g of cinnamic acid and transferred it to a 20mL test tube using a funnel.
12:10 - Started to heat about 200mL of water in a 250mL beaker. The initial temperature was about 27C.
12:12 - 10mL of methanol was measured using a graduated cylinder.
12:20 - 10mL of methanol was added to the 4.9g of cinnamic acid in the 20mL test tube. parafilm was used to cover the top and a hole was poked through the parafilm
12:22 - the test tube was taken to the water which should have been hot, but the hotplate was not
properly so the water was moved to another hotplate and set to 410C.
12:38 - the test tube was lowered into the beaker of water when the temperature was about 70C (the temperature of the hotplate was then adjusted to 105C to prevent the water temperature from continuing to rise)
12:43 - the contents of the test tube started to steadily boil. At this point, most of the solid in the test tube dissolved while the rest went to the bottom of the tube.
12:44- Took the test tube out of the water bath. Temperature is at 68C.
12:48 - Transfered the supernatant into another 20mL test tube while it was still hot.
12:51 - Put the 20mL test tube of the supernatant into a 27C (try to make it 25C) water bath.
12:56 - Precipitate appears. Temperature of water bath is 25C.
12:57 - Inverted a couple of times.
1:03 - Weighed the 5 mL volumetric flask and found it to be 16.3349g
1:15 - 5mL of Pure methanol in the 5mL volumetric flask weighed 20.2864g.
1:23 - The empty 5mL volumetric flask was weighed again after all contents were dried and was found to be 16.3349g.
1:28 - The 5mL volumetric flask with the supernatant was found to be 20.6406g.
14:19 - Pour out the methanol and dry properly and add 5mL of the supernatant, using a pipet.
14:22 - The 5mL of supernatant and flask weighed 20.6406g.
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