Researcher

Jianbo Zhao

Objective

The object of this experiment is to compare how the measured density of pure methanol varies using the same flasks and flasks which have the same or different volumes.

Procedure

1. Set up all the equipment. Which have 3 of 25ml, 3 of 10ml, 4 of 10ml, 4 of 2ml and 2 of 1ml.
2. Clean and dry all of them. Weight each empty flask with cap on.
3. Use pipe to transfer pure methanol into each volume flask and measure them with cap on.
4. Clean and dry them and do two more times. Set as Runs 2 and 3.

Results


Measurement
Measurement(same flask)--same measurement sheet as above

Plot of standard deviation with flask volume
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Plot of mean with flask volume

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4.jpg

Pic.1 Count of all clean volume flasks

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Pic.2 Finish measuring all flaks with pure methanol for Run 1

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Pic.3 Clean flasks with acetone.
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Pic 4 Drying the flasks

Discussion

From the data and experiment result, I can get several things to discuss which are as follows:
  1. From the chart, we can see that despite 1ml, the standard deviation is decreasing as the volume of flasks increasing.
  2. Despite 1ml, the density of measured are in a range from 0.78g/ml to 0.79g/ml.
  3. During the experiment, I cleaned the flasks with acetone is not ideal. But I don't think it influenced the results.

Conclusion

Despite the measurement of 1ml volume flasks, we can easily found that as the flasks volume increased, the standard deviation decreased. The same as mean number. However, there was probably some error of measuring the volume during experiment which causes an error number of 1ml flasks data.

Log

2010-09-24

10:40 Start to wash flasks
11:26 Start to dry flasks with air.
10:00 Set up all the equipment. Count each volumes of flasks and take Picture 1.
10:04 Start measure empty flasks with cap on them. As some of them has not marked by the previous Experiment 180. I marked some.
10:22 Finish measure the flasks with pure methanol and I found that the bottom of the methanol is a little lower. However, it is just for experiment 1 and has very little influence of the flasks
10:51 Finish measure trail 1 and take Picture 2
10:52 Wash flasks with acetone and take Picture 3 . However, I should not swithc the solvents. But it has little influence towards our goal of experiment.
11:08 Dry the flasks and take Picture 4
11:22 Start trail 2
11:55 Finish measure empty flasks and pure methanol. Wash the flasks

2010-09-29

15:10 Set up all the equipments again and do Trail 3. Dry all flasks.
15:12 Measure each empty flasks.
15:21 Measure the mass each flasks with methanol in.
16:04 Finish the experiment, clean all flasks.