J.R. S. answered • 04/12/18
Tutor
5.0
(145)
Ph.D. University Professor with 10+ years Tutoring Experience
Are you asking about the actual recrystallization process or only filtration and drying. Since the question states "filtration and drying", I'll address those only.
Using hot gravity filtration, you will want all components to be heated, i.e. not only the solution being filtered, but the collecting beaker, the funnel and the filter paper. The filter paper should also be fluted. It helps to keep the collecting beaker hot during the entire filtration process. If using vacuum/suction filtration, use the correct size funnel and filter paper. Use the maximum amount of vacuum and be sure to rinse the material collected on the filter paper with pure solvent when finished.
Drying is best accomplished by spreading out the crystals to increase surface area. Drying doesn't really affect purity because if it is still impure at this point, nothing will change that. Of course, if not careful, you could possibly introduce an impurity during the drying process by using dirty or contaminated equipment.
Sami F.
Also what can I say for accuracy for aspirin experiment
Report
04/12/18
J.R. S.
tutor
Filtration DOES affect purity, if done correctly. There is an entire procedure for RECRYSTALLIZATION, which is meant to increase the purity of a substance. It is based mainly on differential solubility of the substance of interest and the impurity. Part of the recrystallization process involves filtration.
I don't know what you can say for accuracy for the aspirin experiment, because I don't know what the aspirin experiment is/was/involved.
Report
04/12/18
Sami F.
Investigation
1)Using the measuring scale weigh out 6 grams of salicylic acid and pour it into the conical flask (100cm3)
Record the mass salicylic acid used.
Record the mass salicylic acid used.
2)Using the measuring cylinder and poured the 10cm3 of the solution of (ethanoic anhydride) into the conical flask and mixed the substances in the flask.
3)With the solution of concentrated sulfuric acid, add 5 drops into the flask and swirl the substances in the flask for a few minutes.
4)Using the bunsen burner heat the flask for approximately 20 minutes in a 400 cm3 beaker which contains hot water should be at 60 degrees. Notice that the temperature in the flask should not be risen above the 65 degrees.
5)After heating the substance, let the flask to cool down as you pour the content of 75 cm3 of water into the beaker. Using the stirring rod to precipitate the solid.
6)Using the buchner flask filter out the aspirin,but under reduced pressure. Be careful that the substances does not touch the skin.
7)Then collect the residue of the crude aspirin of the double thickness of the filter paper and let it to dry.
Report
04/12/18
J.R. S.
tutor
The only thing I can say about the aspirin experiment is that it will have impurities as described. This is not saying anything about the "accuracy" of the experiment. I don't even know what that means. But aspirin is slightly soluble in water, so adding the water to precipitate the product means you'll get a lower yield unless you let it cool down to room temperature, where it is less soluble than at 65ºC. Not much else I can say about this. It's a classical experiment in high school and college chemistry courses. You could increase purity (but decrease yield) if you take the product and recrystallize it by dissolving it in hot water, then allowing to cool and filtering.
Report
04/12/18
Sami F.
04/12/18