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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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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KINETICS OF THE ACID DECOMPOSITION OF THIOSULFATE Aqueous solutions of thiosulfate‚ S2O32-(aq) are stable if neutral or basic‚ but decompose quickly when the thiosulfate is dissolved in acid according to the equation: Sulfur dioxide is a gas at room temperature‚ but is very soluble in water. Sulfur‚ a water insoluble solid‚ forms a colloidal suspension. As a result‚ the solution first becomes cloudy and then opaque. We can take advantage of the developing opacity of the reaction system to do a
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Introduction to Acids Base chemistry Purpose How to determine the constant equilibrium of an acid‚ Ka? How to evaluate the concentration (M) of an acid? In “part A” experiment‚ we would test the PH of different concentration of acetic acid (a weak acid which partially dissociated in water) with a PH probe. After we got the PH‚ we could find out the concentration of H+ by applying the relationship pH = -log [H+]. Having the determined value of [H+] of a weak acid with a known molar concentration [HA]‚ The
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CHAPTER 1 Introduction Background of the Study Like many other hygiene convenience‚ shoe polish or can also be called boot polish is usually a wax ‚ cream or paste used by people to shine‚ water proof and restore the appearance of leather shoes. This extends the footwear’s life. This is made up of many kinds of chemicals and because of this; it can cause irritations‚ allergies to us. In our generation‚ shoe polish is used every day and companies produce a lot of it to meet the demands of
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one of two very similar pentose rings. Ribonucleic acids contain the sugar ribose. Deoxyribonucleic acids contain the sugar deoxyribose. The only difference between these two sugars is that deoxyribose contains one oxygen atom less than ribose. Pentose sugars are essential because they are involved in linking different nucleotides together by condensation reactions. The Nitrogen-Containing Bases There are two types of bases found in nucleic acids. The purine bases have two nitrogen containing rings
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of Shikimic Acid‚ intermediate for the production of Oseltamivir‚ the Avian Flu drug Supervised by: Dr. Reza Yegani Dr. Mohammad Hossein Sarrafzadeh Mr. Habibollah Ramezanzade by: Kaveh Yazdifard Presented on: 1385/10/3 Contents Acknowledgement Introduction Shikimic Acid & its Natural Properties Derivatives of Shikimic Acid Avian Flu Sickness‚ Medications Oseltamivir and Shikimic Acid’s Role in Synthesis Production of Shikimic Acid Extracting Shikimic Acid from the Plant
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ACID/BASE You might need to know the following K values: CH3COOH Ka = 1.8 x 10–5 Benzoic Acid Ka = 6.5 x 10–5 HNO2 Ka = 4.5 x 10–4 NH3 Kb = 1.8 x 10–5 HF Ka = 7.2 x 10–4 H2S Ka = 5.7 x 10–8 HSO4– Ka = 1.2 x 10–2 HS– Ka = 1.2 x 10–13 HCOOH Ka = 1.8 x 10–4 HOCl Ka = 3.0 x 10–8 SIMPLE ACIDS AND BASES 1. According to the Brønsted–Lowry definition‚ which species can function both as an acid and as a base? (A) Cl– (B) SO42– (C) NH4+ (D) HCO3– (E) H3O+ 2. Which of the following
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Biomes Comparison Essay Ecologists group earth’s diverse environments into biomes. A biome is a complex of terrestrial communities that develops a large area and is characterized by certain soil climate conditions and particular assemblages of plants and animals. Not all species live in every biome they vary in their adaptations to different conditions. An adaptation is an inherited characteristic that increases an organism’s ability to survive and reproduce. These sorts of variations in plants
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Acids‚ Bases and Buffers Lab Acids‚ Bases and Buffers Lab Results: The experimental results for part one is as follows: Part One Data Table | Initial pH | Final pH | Test Tube A | 6 | 1 | Test Tube B | 4 | 4 | Test Tube C | 4 | ----- | Test Tube D | 4 | 4 | Test Tube E | 6 | 11 | The experimental results for part two is as follows: Part Two Data Table | Before CO2 was Added | After CO2 was Added | Colour | Blue/green | Light green/yellow | pH Level | 8.0pH | 5.0pH |
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