Researcher

Jianbo Zhao

Objective

The objective of this experiment is to determine the required time (30 min or 60 min) for cinnamic acid to reach saturation in methanol when heated to 40C then cooled to 25C.

Procedure

1. Set up all the equipments. Including temperature bath, tubes, balance and volumetric flasks
2. Take out 2 clean tubes label them as A1 and B1.
3. Started to measure the mass of Cinnamic Acid. With the calculation it would be around 3.8g
4. Put each tube with Cinnamic Acid. Add up pure methanol into both tubes. Until 3 quarters of the whole tube, stop.
5. Put on the cabs and seal the tube really tight.
6. After that, use a tape to take the two tubes together. Tape them on on the edge of temperature bath which they can stick with each other. Set the temperature into 41C and put them in.
7. 30 minutes later, take tube A out and transfer the liquid into a new clean tube marked as A2.
8. 60 minutes later, take tube B out and transfer the liquid into a new clean tube marked as B2.
9. Bath A2 and B2 with a beaker with 25C water about 10 minutes.
10. Take a new 5ml volumetric flasks. Weight the empty one and weight the total amout of the flask and pure methanol. Then clean it, add solution A and measure the mass.
11. Take a new 1ml volumetric flasks. Weight the empty one and weight the total amout of the flask and pure methanol. Then clean it, add solution A and measure the mass.
12.Take a new 1ml volumetric flasks. Add solution B and measure the mass.

Results

The measurements

Volume of Flask(mL)
Measured Concentration (M)
5
1.161
1
1.343
1
1.305

For the solution. My result 1.43 which I think there were some error while doing the experiment.
100921_100940.jpg
Pic.1 Use funnel to translate Cinnamic Acid into tube
100921_103054.jpg

Pic.2 Add pure methanol up to 3 quarters of both tubes
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Pic.3 tape 2 tubes onto temperature bath

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Pic 4. Measurement of mass for solution

Discussion

In both tubes with the bath temperature of 40C. First, 30 minutes is not enough for saturating the solution. Second, 60 minutes bath at 40C is long enough to get a saturate solution. It appeared much obviously and faster than the 30 muinutes one. We can also assume that the exact number is between 1.2 and 1.5. However, the number at 21C will be around 1.4 of the solution. From the observation, we can see that the value around 1.5M is corresponded to a saturation. By observing the water bath at 41C. We found that 30 minutes are not enough to saturate as no some crystal is still inside the tube. However, bath 60 minutes are good enough to saturate the solution. As no crystal are found in the tube.

Conclusion

In conclusion, the solusions with different bathing time saturations. My measurement in flask 5ml and 1ml is around 1.4. Which I has1.43, which is not saturated. It is the only number in my experiment. Besides, the 60 minutes temperature bath is much more influenced than just a 30 minutes bath. The required heating time for this solution is no less than 1 hour. Thus, I get a saturated solution and a solution has a number of 1.305M.

Log

Date :21,Sept, 2010
0946 Set up equipments. Set temperature bath to 29C
0959 Measured the Cinnamic Acid mass:3.8515g
1009 take picture 1 of tube funnel. However, some splited out. Thus, measured the weuight of tube B directly.
1019 Measurement of tube B with Cinnamic Acid:3.5755g
1029 Add up methanol into tube A and B about 3 quarters mark of the tubes. Take picture 2
1033 Seal tubes. Take picture 3.
1038 set the temperature bath to 41C
1108 Take tube A out, transfer solution A into Tube A2. Cabbed 2 of them. There was no solution at the bottom of the tube.
1118 Put A2 into water bath at 25C
1138 Take tube B out, transfer into another tube as B2, then put it into the same water bath.
1155 Bath temperature decreases to 21C. There was some crystal came out at the bottom of the tube.
1201 Measure solution A.the mass of empty 5ml flasks is 10.268g. The total pure methanol mass is 14.1162g and the total solution A is 14.4454g
1210 The mass of emply 1ml flasks is 20.3793g. The total pure methanol mass is 21.1556g and the total solution A is 21.2307g. Take picture 4
1219 Measure solution B. the mass of emply 1ml flasks is 20.3793g. The total pure methanol mass is 21.1556g and the total solution A is 21.2286g