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Solubility book (3rd Edn)
Lizzie Clark with Samantha Gaines
To calculate the solubility of trans-cinnamic acid in 1-octanol by the density method.
25 mL volumetric flask
Hot Water Bath
1. Put on safety gear including goggles, lab coat, and gloves.
2. Gather the materials listed above.
3. Measure the temperature of the room (preferably in Celcius to make later calculations easier).
4. Using the electron balance, weigh the empty 25 mL volumetric flask (g).
5. Carefully pour 25 mL of 1-octanol into the volumetric flask.
6. Using an electronic balance, measure the weight of the filled volumetric flask and 1-octanol.
7. Add a small amount of trans-cinnamic acid to the 1-octanol and swirl until dissolved.
8. Place beaker in warm water bath of around 40C for one minute.
9. Repeat steps 7 and 8 until precipitate does not dissolve, gradually increasing the temperature of the water bath each time.
10. Weigh new empty flask and tarr.
11. Pipette 25mL of 1-octanol + trans-cinnamic acid solution into flask and weigh.
The solubility of trans-cinnamic acid in 1-octanol is measured to be 0.45019555039598 M
The observed solubility of trans-cinnamic acid in 1-octanol of 0.45019555039598 M was comparable to the average measured value of 0.533 M. This measured average was obtained from the
ONSchallenge list of the solubility of cinnamic acid in organic solvents
10:01- Room temperature taken at 20.1C.
10:02-Measured the weight of the empty 25 mL volumetric flask to be 20.2680g. Zeroed scale.
10:12- Measured weight of 25mL flask+ 1-octanol to be 40.7876g.
10:25- Poured 30mL of 1-octanol into a 100mL beaker and added cinnamic acid with a spatula.
10:30- Added cinnamic acid until it would no loner dissolve at room temperature.
10:35- Placed 100mL beaker in hot water bath at 40.0C
10:39- Removed beaker and swirled. There was still undissolved solvent so the beaker was returned to the bath.
10:41- Removed beaker and swirled. There was still undissolved solvent so the beaker was returned to the bath.
10:48- Removed beaker and swirled. There was still undissolved solvent so the beaker was returned to the bath.
10:52- Removed beaker and swirled. There was still undissolved solvent so the beaker was returned to the bath.
10:55-Removed beaker and swirled till solute dissolved.
10:57- Solute completely dissovled. Placed beaker in room temperature water bath with parafilm covering the top.
*Note: Naturally white cinnamic acid tints the naturally clear 1-octanol a light yellowish color.
11:11- Still no crystals formed, so more cinnamic acid was added and the beaker was replaced in the hot water bath at 40.0C
11:18- Removed and swirled, solute not dissolved, replaced in hot water bath.
*Note: Do not directly inhale, but (through wafting) a lemon-like scent can be observed from the solution.
11:23- Removed beaker and swirled. The solute dissolved after vigorous swirling.
11:24- Parafilmed beaker and placed it in room temp water bath (18.9C) for attempt #2 at forming crystals.
11:33- No crystals formed. Added more cinnamic acid.
11:34- Placed beaker in hot water bath at an elevated temperature (42.2C)
11:42- Bath temperature at 44.0C. Removed beaker and swirled. Solute still present, so the beaker was replaced into the hot water bath.
11:46- Water bath temperature now at 46.1C.
11:48- Removed and swirled beaker. Solute nearly dissolved.
11:49- Replaced in hot water bath, now at 47.9C.
11:52- Removed beaker. Solute fully dissolved when swirled.
11:53- Put parafilm over beaker and placed in room temperature water bath (19.7C).
12:07- No precipitate observed. More cinnamic acid added.
12:09- Replaced beaker in hot water bath, now at 52.0C.
12:12- Swirled every three minutes until all solute dissolved.
12:21- All solute dissolved, solution is a clear yellow liquid. Beaker parafilmed and placed in room temperature water bath.
12:30- Observed crystals forming.
13:15 A lot of crystals have formed leaving a slush with just a few mm of supernatent above the slush.
13:16 Filtered supernatant through filter paper into another beaker.
14:00 Weighed empty 25 mL volumetric flask: 20.2815g and zeroed scale.
14:01 Pipetted supernatant from beaker into volumetric flask.
14:07 Weighed flask containing supernatant: 21.0986g
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