Preview

recrystallization of Benzoic acid

Good Essays
Open Document
Open Document
879 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
recrystallization of Benzoic acid
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 water) were used to identify which one is an ideal solvent. An ideal solvent is insoluble in room temperature and soluble in hot solvent. 0.5mL of each solvent were added into four reaction tube with 25mg`of pure Benzoic acid. After careful observation, distilled water fit the requirement. During recrystallization, 0.5 grams of Benzoic acid were added into a 50mL flask with 10 mL distilled water. After performing this experiment, the first crop had a mass of .334 grams with a second crop of 0.0grams. The percent recovery yields 66.8%, which means that according to expected value of 70% this data confirms that the Benzoic is pure. Finally, the melting range was between 120 to 122 degrees which again confirms that the recrystallized Benzoic acid has been purified completely.

INTRODUCTION

Recrystallization is a commonly used method of purifying solid compounds. Insoluble impurities get extracted from the compound by dissolving the mixture in hot solvent. The soluble impurities are dissolved in a high temperature environment and the solvent is cooled in room temperature while Benzoic acid crystallizes. The crystalized Benzoic acid is then placed in an ice bath to cool it further. The crystals are then filtered out using the vacuum filtration provided in lab. The filter paper is taken out and crystallized Benzoic Acid is dried out. Overall, the prediction for this experiment would be that the percent recovery will yield a low outcome.

Purifying Benzoic acid by using

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Chem 1211K Lab Report

    • 1855 Words
    • 18 Pages

    The identification of the melting point of the organic acid was done to find another characteristic of the acid and to test the purity of the recrystallized pure acid. A 2-4 mm layer of unknown sample was placed into a capillary tube sealed on one end. Then the capillary tube was inserted into the side a Bibby Sterlin device. The plateau was set to 200°C on the melting point apparatus. Once the plateau temperature was reached, the sample was watched carefully. When the sample first began to melt and when it was fully melted was recorded. These numbers were the range of the melting point. A slow melting point of the unknown organic acid and a standard sample was completed next. A new plateau was set about 10°C lower than the observed melting point of the unknown sample. This time once the plateau was reached, the heating was no more than 1°C per minute. This gave a much more accurate read of both melting points. If the standard did not melt in the range listed on the label of the bottle, that meant the machine was not working properly. The standard sample and the unknown organic acid melted in their appropriate ranges.…

    • 1855 Words
    • 18 Pages
    Satisfactory Essays
  • Better Essays

    orgo lab

    • 993 Words
    • 4 Pages

    Purpose: The purpose of this experiment was to recrystallize a 95% pure sample of benzoic acid contaminated with approximately 5% salicylic acid using two different methods to determine the melting points and discover the impurities of the substance.…

    • 993 Words
    • 4 Pages
    Better Essays
  • Satisfactory Essays

    Organic Lab 2583-4

    • 503 Words
    • 3 Pages

    The purpose of this lab is to purify solids contaminated by relatively small amount of impurities by a technique called Recrystallization. Compounds that have different solubility at different temperature usually can be recrystallized.…

    • 503 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    5) Using the cooled solution of benzoic acid crystals, filter out the benzoic acid from the table salt using funnels.…

    • 522 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    Sodium Benzoate is a common food preservative used in food products such as jams and jellies, soft drinks, pickles, condiments etc and in tinned products in the market. This experiment aimed to determine whether benzoic acid is formed from it’s superior soluble form sodium benzoate in stomach acid, which is simulated by HCl (pH=2). It has been seen that at a low optimum pH, i.e. in the presence of sufficient hydrochloric acid, sufficient benzoic acid is yielded. The percentage yield is determined from the calculations of the theoretical (stoichiometric) calculations and the actual yield from the reaction. Also throughout the experiment, some basic laboratory operations such as measuring mass and volume, separating solids from liquids by vacuum filtration and drying solids are familiarized with.…

    • 1347 Words
    • 6 Pages
    Powerful Essays
  • Good Essays

    1. Recrystallization- Purify a crystal. Find a solvent that dissolves the crystals when boiling, and recrystallizes when cool. (The same solvent should not dissolve it when cold). A crystal is extremely organized,…

    • 922 Words
    • 4 Pages
    Good Essays
  • Good Essays

    Wintergreen Oil Synthesis

    • 515 Words
    • 3 Pages

    Important process of isolation that is commonly used is to vacuum filter a solution that allows for the separation of insoluble substances present in a solution. The decision to choose vacuum filtration against another method such as gravity filtration is due to the suction pressure in vacuum filtration that creates faster and more effective suction [1]. Once separated, purifying a substance can occur by recrystallizing the solid substance by heating it in water to its boiling point, making it fully dissolved and soluble due to the added source of energy. Then reversing the conditions by cooling the solution, allows pure substance to form crystals at a higher temperature with other ‘like’ crystals that make the substance more pure, while the impurities remain dissolved in the solution till the solution is further…

    • 515 Words
    • 3 Pages
    Good Essays
  • Better Essays

    Chem Lab

    • 858 Words
    • 4 Pages

    There are millions of different organic compounds. Most of them are found in mixtures and in order to achieve a pure form they need to be separated, isolated, and purified. However, there are endless numbers of possible mixtures, which make it impossible to have a pre-designed procedure for every mixture. So chemists often have to make their own procedures. The purpose of this experiment was to prepare the student to the real world by them designing their own procedure which will help them understand the techniques of separation and purification better. The goal was to extract two of the components of the mixture that consisted of 50% benzoic acid, 40% benzoin, and 10% dibromobenzene. The benzoic acid was extracted by the use of base and extraction technique. Then a crystallization was performed in order to separate benzoin by the use of hexane a solvent, leaving the dibromobenzne in the mother liquor. The percent recovery for benzoic acid was 91.8% and 80.3% for the benzoin. The MP for benzoic acid was 119-122°C (1) and 135-136°C (2)for the benzoin. The high percent recovery and closeness of measured MP to the literature value indicate that the designed procedure was successful.…

    • 858 Words
    • 4 Pages
    Better Essays
  • Satisfactory Essays

    Multistep Synthesis

    • 669 Words
    • 3 Pages

    In this experiment, benzoin was oxidized by nitric acid to benzil, which in turn was rearranged to benzilic acid. Prior to beginning the experiment, the theoretical yield of benzil was discovered. The limiting reactant in the reaction, benzoin + nitric acid benzil, was benzoin at 0.00141 moles. This value was discovered by the initial amount of the reactants used: 0.30 grams benzoin and 1.5 ml Nitric Acid (see Eq 1). Using the moles of the limiting reagent benzoin, the theoretical yield of benzil was calculated to be 0.296 grams (see Eq 2). Before crystallization, the…

    • 669 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    To study the affect of pH on a food preservative. Sodium benzoate changed into benzoic acid once the 3 M of HCl was added making it a pH of 2, making the solution acidic. The hydronium ion concentration was high enough that it gave a yield of benzoic acid, which, is very insoluble in water and it formed a precipitate in the solution. The end percent yield was 132.352%, this was due to a few flaws in the experiment. During the filtration process of the experiment the funnel was not working properly and not all the…

    • 690 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.…

    • 1426 Words
    • 6 Pages
    Good Essays
  • Powerful Essays

    Benzil Reduction

    • 965 Words
    • 4 Pages

    The objective of the experiment was to reduce Benzil, using sodium borohyride as the reducing agent. In a benzil reduction, there are five possible products than can occur, specifically a racemic mixture of benzoin, racemic mixture of hydrobenzoin, or meso-hydrobenzoin. Therefore, three different tests were conducted in determining the identity of the product: melting point, thin light chromatography, and infrared spectroscopy.…

    • 965 Words
    • 4 Pages
    Powerful Essays
  • Satisfactory Essays

    Assessment of sample purity for a known substance. By comparing observed range for an actual sample to the known range for a pure sample, I can tell whether my actual sample is pure or contaminated (the range is depressed and broadened). So, In part A, melting point of benzoic acid was observed in range 122 to 125 ¨¬C. By comparing melting point of benzoic acid (121 ¨¬C) with result from part A, the result is little higher than the pure melting point. So I can tell it is little contaminated.…

    • 521 Words
    • 3 Pages
    Satisfactory Essays
  • Better Essays

    Measuring melting points of benzoic acid and mandelic acid. Capillary tubes were loaded with benzoic acid and mandelic acid powder at about 1-2 mm. Tubes were placed inside the melting apparatus to be heated. Since pure benzoic acid melts at 122-123˚C, the tube was rapidly heated to 110˚C and heated slowly to 1-2˚C per minute till all crystals liquefied. And the same applied to the mandelic acid capillary tube.…

    • 1111 Words
    • 5 Pages
    Better Essays
  • Satisfactory Essays

    After all of the nitric acid was added the mixture was then warmed to room temperature. After 15 minutes, it was then poured into a 250-mL. The solid product was isolated by suction filtration using a small Buchner funnel.…

    • 479 Words
    • 2 Pages
    Satisfactory Essays