EXPERIMENT 2: Recrystallization and Melting Point Recrystallization (or Crystallization) is a technique used to purify solids. This procedure relies on the fact that solubility increases as temperature increases (you can dissolve more sugar in hot water than in cold water). As a hot‚ saturated solution cools‚ it becomes supersaturated and the solute precipitates (crystallizes) out. In a recrystallization procedure‚ an impure (crude) solid is dissolved in a hot solvent. As this solution is cooled
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BENZOIC ACID & BENZOATES (210 –218) • Retards growth of bacteria and yeasts • Occurs naturally in many foods – a similar distribution to salicylate (but at a lower dose than as an additive) • Common food sources: Soft drink‚ cordial‚ fruit juice and cider Liquid essences and syrups Iceblocks‚ jelly‚ low joule jam‚ dips‚ pickles‚ olives Fish marinades and preserves • PABA (para-amino-benzoic-acid)
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Recrystallization of Benzoic Acid Objective To purify benzoic acid by recrystallization and gain experience with a basic organic laboratory techniques. Background Products of chemical reactions are often contaminated with impurities. One method for purifying chemicals‚ recrystallization‚ takes advantage of the differences in the solubilities of the desired products and the impurities and the tendency for the slow formation of crystals to exclude impurities from the crystalline solid. HC HC
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Crystallization of Benzoic Acid Purpose: The purpose of this experiment is to purify benzoic acid by crystallization. Procedure: 1. 0.5g impure benzoic acid was placed in a 50mL Erlenmeyer flask. 15mL of water was added and the mixture was heated to a boil on a hot plate. 0.5mL of water was added to the flask‚ while swirling the flask. The mixture was boiled until the benzoic acid completely dissolved. The total volume of water used was recorded. The black solid that remain in the dissolved
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Introduction Extraction is a purification technique used in organic chemistry to separate compounds from a mixture of two or more compounds. There are three different extraction techniques: liquid-liquid extraction‚ solid-liquid extraction and chemically active extraction. All three types of extraction follow the same principle. Organic molecules dissolve in organic solvents and polar molecules dissolve in aqueous solvents. This phenomenon is observed because of the intermolecular forces between
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Introduction: The theory behind the extraction of a solution containing benzoic acid‚ cellulose‚ and methyl orange involves many components pertaining to the fundamental ideas of solubility and polarity. Using the concepts of like dissolving like and acid base reactions‚ a solution of organic acid (benzoic acid)‚ a water soluble compound cellulose‚ and an organic soluble compound methyl orange‚ can be separated and benzoic acid can be isolated by a method of extraction. At the fundamental level
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Abstract The objective of this experiment was to observe multi-step purification of benzoic acid after performing the extraction from a mixture containing benzoic acid‚ cellulose‚ and methyl orange. Recrystallization was done to remove impurities from the sample. The amount of BA recovered during recrystallization is much less than the extracted amount of BA. The difference between the pure and impure samples was observed by comparison of melting points. It was found that impure samples will have
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Mabel M. Kimble September 21‚ 2014 Chemistry 234 Recrystallization of Benzoic Acid ABSTRACT The recrystallization of Benzoic Acid was performed to fully master the ability to purify a solid compound. This form of purification technique is especially important in chemical identification‚ where the melting point of the compound is taken to confirm its purity. In order to perform recrystallization a solubility test much be completed. Four solvents (95% Ethanol‚ Petroleum Ether‚ Acetone and distilled
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Recrystallization of Benzoic acid Chemistry 204-002 Date: 4/9/2011 Hector Ortega Recrystallization is a method used to purify compounds‚ and this is a very important procedure because compounds are naturally impure. Polarity and solubility play a big role in this experiment and these characteristics are exploited in order to have a crystallization of the desired compound. In this experimented benzoic acid was crystallize using ethanol and water. I chose these solvents based on part C of the experiment
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Benzoic Acid and Benzoates in Food‚ Drinks and Medicines Benzoic acid and benzoates are common additives to food‚ drinks‚ medicines and cosmetics‚ and they also occur naturally in many plants. They are useful chemicals in manufactured products because they kill or inhibit both bacteria and fungi and can act as preservatives. Benzoic acid and benzoates are considered to be safe chemicals for humans when they’re used in small quantities‚ but there are at least two situations in which even small
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