Crystallization: Lab Report
The purpose of this lab is to understand the concept of purification through crystallization. Crystallization is the process of purifying a substance, with the most adequate solvent. The process of crystallization came to be based on the principle of solubility. First, we must choose a solvent. The solvent is crucial to crystallization because it’s what will allow impurities to dissolve. Therefore, when selecting a solvent it is important that it does not cause a chemical or flammable reaction to the substance. Then, we continue with the process until the solution is ready to be filtered using the Buchner funnel. During filtration the pure substance will completely separate from the impure substances completing our experiment. Procedures
As stated above, first choose a solvent, for this particular experiment we will be using solvent H2O. using a hot plate bring to a boil 0.5 g of impure Benzoic Acid and about 10ml of the H2O, if Benzoic Acid has not dissolved continue adding small portions of H2O. Once completely dissolved place the flask in an ice bucket to cool the solution, you should see white crystals forming. We must then separate the crystals from the liquid by doing a vacuum filtration using Buchner funnel. With cold H2O wash the crystals, dry with filter paper, and weight the crystals to find percent yield. Observation/ Result
During the process, benzoic acid was slightly soluble in water; crystal substance on top of water. Completely dissolved in heat bath. Ones it was completely dissolved, and after the vacuum, the pure benzoic acid start to appear on top of the filtration paper with a pearl color. At the end of the ice bath the benzoic acid start the recrystallization. The purified and end product of the experiment was .20 grams of pure benzoic acid.
Finally, the percentage recovered and purified benzoic acid was 40%. Based on this fallowing calculation .20 grams of benzoic acid multiplied...
References: Experimental Organic Chemistry, 2nd edition. Charles Wilcox and Mary Wilcox
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