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Solubility book (3rd Edn)
The objective of this experiment is to determine the solubility of Benzoic acid in methanol, chlorofrom and hexane.
Set up three tubes which have three solutions. First, measure three pure solvent and then measure those density of solutions.
[Some of these are impossible - you mixed up numbers in the sheet JCB]
Average Measured Concentration (M)
Pic.1 Put three sealed tubes into water bath set as 41C
Pic.2 Bath for 1 hour and take them out.
Pic.3 Bath three tubes into water at room temperature
Pic. 4 Measure three density into different volume of flasks
Due to the experiment, chloroform solve a lot into solute. And hexane is the second more solve into solute. Methonal is the third.
#During the experiment, the hexane benzoic acid solution's concentration is much less than those two solutions.
The concentration of methanol, chloroform and hexane in benzoic acid solution is 15.31M, 20.41M and 0.272M at room temperature.
[wording incorrect (and spelling) JCB]
The concentration of hexane in benzoic acid is much less comparing to other two solutions.
Date: Jan. 25th, 2011
12:45 Find 3 new tubes. Put Bezoic acid into each tube. Labeled them as A, B and C. Calculate the mass and put in around 4g. Measured each mass.
13:09 Started to measure pure solvents. Hexane. methanol and chloroform with different volume of flasks, which is 10ml, 5ml, 2ml, 1ml.
14:05 Set up water bath to 40C
14:07 Put in different solvent in each tube. Added up to three quarters of the whole tube.
14:17 Sealed the tubes and put them into a beam for water bath.
14:50 The actual temperature wento to 41C. Put three sealed tubes into a beam
[do you mean beaker? JCB]
and put it into the water bath. Take
15:50 Take three tubes out. See the crystal above in tube 3. Lots of crystal in tube 1 which is hexane solvent. Little saturation in Chloroform solvent solution. Take
[Did you take the temperature at this point? From the image I don't think that bath would last very long at 40C JCB]Yes, it was 40C at that point. Actually the temperature of the liquid in the beam is the same as the liquid in water bath.-James
15;53 Transfer three clear liquid to three new tubes, marked as A1 B1 and C1.
[Did you have trouble getting a clear solution from the chloroform sample? It floats so how did you avoid transferring over some solid? JCB]
15:59 Take a beam and put water inside, then bath three tubes. Recorded the water temperature which is 14C, take
[Are you sure 14C? JCB] Yes, I measured it.
16:07 Take them out and started to measure the density of each solution with various volume of flasks. Take
[Did you see solid come out after it started to cool? 8 min is probably not enough time to equilibrate - also 14C is very far from room temp - 25C is where the second bath should be JCB]
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