Words: 1412
Additionally the boiling point temperature was upturned at the point when the solution in the boiling flask first began to boil. This temperature was gathered in hopes to compare with the known and documented boiling points of methanol and water in chemistry encyclopedias. However, this temperature was found useless as the location of the thermometer was at the top of the distillation apparatus and the boiling occurred at the bottom of the apparatus, thus the boiling point temperature gathered was inaccurate.
The temperature that was being gathered was the vapor temperature once the vapor finally reached the top of the apparatus. A 25 ml graduated cylinder was used to collect the 1 ml sample of the distilled solution as it dropped from the distillation apparatus. Due to lack of 10 ml graduated cylinders, a potential error could be that too much or too little solution was gathered; not an exact 1 ml sample was collected due to size of cylinder. This solution was then weighed and ran through the refractive index machine.
An additional graduated cylinder was used to collect the next 1 ml sample while the 1st sample was being weighed and refractive index collected. To weigh the 1 ml sample, a small beaker was set in a zero gravity call to be calibrated to zero, once calibrated, the 1 ml sample was transferred from the graduated cylinder to the beaker and weighed. A potential error in this weight would be that not every drop made it out of the cylinder before weighing therefore providing a less than accurate measurement. The weights and refractive indexes were recorded in table 1. . Additionally the actual weight and refractive index of 1 ml solution of Methanol was collected from an internet encyclopedic source, in order to compare the accuracy of a simple distillation apparatus. Our final weight of 1. Egg/ml is 0. 42 g/ml heavier than the 0. 791 g/ml weight found on the internet source, therefore showing that our distilled solution was not 100% distilled of all contaminants and needs to be further distilled. Additionally the refractive index of our distilled sample was 1. 199 and the actual refractive index of methanol is 1. 326.
Our results reflect an additional error in collection. Our final three ml of sample was collected together rather than in 1 ml increments therefore our weights and refractive index are averages of all three. A possible method of collection that could be used is to use a graduated yielder to collect 1 ml samples, once each ml is collected, immediately transfer to a small, labeled, beaker and set aside until end of collection before weighing. This will ensure enough time is allotted for the accurate gathering of 1 ml samples. This method is used in phase Ill.
Phase II of the experiment was set up exactly the same as phase l, however water was mixed with the methanol solution in the boiling flask. The purpose of this phase of the experiment is to separate the two solutions using different boiling temperatures in a simple distillation apparatus. Again the initial temperature as gathered to have a base line temperature before beginning the distillation. Also the boiling point temperature was gather, however later determined it was not necessary. The First drop temperature was recorded as well. This temperature reading is used to determine which solution is being collected.
If the temperature read roughly ICC the solution being gathered is Methanol, however if the temperature read roughly ICC the solution being gathered would be water. This temperature is important as it gives us a rough idea of what we are collecting. From our data under Phase II, we know that the solution initially being gathered was Methanol since the temperature of the first drop was roughly ICC. Again the solution was gathered in a 25 ml graduated cylinder and the weight and refractive index was collected for each ml collected and recorded in table 1. 2.
Like Phase I after each ml sample was collected, an additional 25 ml graduated cylinder was used to collect the next ml sample as the first sample was being weighed and refractive index recorded. The same errors could be found in Phase II as where found in Phase I due to the size of the graduated cylinder and transfer from cylinder to beaker. Our results of 1. 04 g/ml are 0. 249 g/ml heavier than the actual 0791 g/ml weight of methanol, therefore showing that our sample is not 100% clear of water and will need further distillation before being properly distilled.
Additionally the 1. 335 refractive index gathered is 0. 009 higher than the actual 1. 326 refractive index for methanol, further showing that our distillation is not 100% distilled. Phase Ill of the experiment was set up like Phase I and II however a fraction column was connected to the boiling flask. The purpose of the fraction column s to cause the rising vapor to cool and condense and then evaporate multiple times as it travels up the fraction column before finally reaching the side arm of the distillation apparatus.
This causes the mixed solution to actually distill multiple times before being collected. From our results in phases I and II this extra tool is beneficial as we found that our distillation needs to be distilled more than once to be completely free of any contaminants. Like phases I and II the initial temperature was gather for a baseline temperature and the boiling point temperature was gathered (again not needed). Furthermore the temperature of the first drop was recorded. The important of this was described above.
From our results we know that Methanol is being collected first since the first drop temperature was ICC. Once the first ml sample was collected, we immediately transferred it to a small beaker labeled “1” and set off to the side for weight and refractive index measurements to be collected at the end of the distillation process. Again we utilized a second graduated cylinder to collected samples as our first graduated cylinder was being emptied and cleaned (25 ml graduated cylinders were used). This was done to prevent the gathering of more than 1 ml sample at a time.
Roughly halfway through the distillation, the temperature jumped into the ICC range indicating that all methanol solution was burned off and collected and the samples being collected now were water. From our results our methanol was done being collected after the 6th ml according to table 1. 3. Sample 7 (7th ml) in table 1. 3 would have some methanol, however it would be mostly water as the temperature had rose from ICC to ICC. The weight of sample 6 (6th ml) was 0. 951 g/ml which was only O. 16 g/ml higher than the actual 0. 1 g/ml indicating that a fractional distillation is better than a simple distillation, however father distillation would still be needed to get a 100% measurement. Again transfer of sample from graduated cylinder to beaker could be a potential error in measurement. Our refractive index tells the same thing as it is 0. 009 higher than the actual refractive index of methanol. The lack of refractive index measurement in sample 10 (10th ml sample) indicates another potential error in both weight measurement and refractive index measurement. The lack of a sample value is due to evaporation of the ample as it sat in the beaker to be measure.
Since this occurred with sample 10 it had to have occurred with all 12 samples as a result our weights and refractive index values could be slightly squid. Away to fix this problem for future experiments would be to cover the sample in the beaker with a wax film to prevent any evaporation to occur. Conclusion: From the results gathered in the three phases, a fractional distillation apparatus is more effective and time efficient than a simple distillation apparatus, because it distills the solution multiple times before finally being collected.
The simple stimulation did not result in an efficient separation of methanol and water, however the fractional distillation did. In the Simple distillation, there was a 0. 249 g/ml higher difference than the actual weight of methanol where as the fractional distillation only had a 0. 16 g/ml higher difference, resulting in a better distillation. The fractional distillation could be improved with better insulation of the fraction column to allow the distillation process to occur more efficiently. Additionally heating the solution in the boiling flask slower would allow for a more efficient separation of methanol and water.