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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The methylene blue staining procedure is used to measure yeast viability based on the assumption that the methylene blue will enter the cells and be broken down by living yeast cells that produce the enzymes which breaks down methylene blue‚ leaving the cells colourless. The non- viable cells do not produce this enzyme (or enzymes) and as such the methylene blue that enters the cells are undegraded causing the cells to remain coloured (the oxidized form concentrates intracellularly). The coloured
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1. Two ships P and Q are moving along straight lines with constant velocities. Initially P is at a point O and the position vector of Q relative to O is (6i + 12j) km‚ where i and j are unit vectors directed due east and due north respectively. The ship P is moving with velocity 10j km h–1 and Q is moving with velocity (−8i + 6j) km h−1. At time t hours the position vectors of P and Q relative to O are p km and q km respectively. (a) (b) (c) Find p and q in terms of t. (3) Calculate the distance
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the concentration of the acid solution changes the rate of the reaction between dilute hydrochloric acid and magnesium metal. • As the metal reacts with the acid‚ hydrogen gas is produced and the metal dissolves. To get an estimate of the rate of reaction‚ the time taken for a small piece of magnesium ribbon to dissolve (disappear) can be measured. This is a “clock reaction” and the reaction rate is proportional to 1/time taken SAFETY Dilute hydrochloric acid is harmful. Wear safety spectacles
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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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The quote above illustrates how Foucault claimed that being aware of constant surveillance created a sense of self-governance. Even tough there was not any set laws due to the fear Big Brother installed‚ the citizens of Oceania lived very precautious‚ uncertain of when or how they would break the law. Winston was constantly blocking out any thoughts not regarding big brother. The constant surveillance consequently created a sense of always policing themselves. Winston made sure he maintained a good
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18.1.4 – 18.1.6 CALCULATIONS INVOLVING ACIDS AND BASES Review of Important formulas pH = ‐ log10[H+] [H+] = 10‐pH pKa = ‐ log10 Ka Ka = 10‐pKa pOH = ‐ log10[OH‐] [OH‐] = 10‐pOH pKb = ‐ log10 Kb Kb = 10‐pKb The ionic product of water = Kw = [H+] x [OH‐] = 1.0 x 10‐14 mol2 dm‐6 at 298 K The expression varies with temperature
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MANUFACTURE OF ACRYLIC ACID BY PARTIAL OXIDATION OF PROPYLENE Submitted by‚ P.V.R.Krishna Prasad. M.Prem Kumar. ACKNOWLEDGEMENT We hereby place our sincere thanks to Dr.R.KARTHIKEYAN‚ Head of the Department of Chemical Engineering ‚ Faculty of Engineering and Technology‚ S.R.M University and the faculty members of Chemical Engineering Department for their full hearted co-operation and encouragement for the completion of this project. We extend our thanks to our Project guide Mr
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Nitric acid is a highly reactive oxidizing agent used in making fertilizers‚ explosives‚ and rocket fuels‚ and in a wide variety of industrial metallurgical processes. It is also a component of acid rain. Its chemical formula is HNO3 and it has been known as “aqua fortis”‚ which means strong water‚ to alchemists. It is a transparent‚ colorless to yellowish‚ fuming corrosive liquid. Nitric acid is a strong acid and therefore it completely dissociates in water. It has a gravity of 1.41 and the concentration
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this experiment‚ you will • Use Hess’s law to determine the enthalpy change of the reaction between aqueous ammonia and aqueous hydrochloric acid. • Compare your calculated enthalpy change with the experimental results. [pic] Figure 1 MATERIALS |LabQuest |2.0 M hydrochloric acid‚ HCl‚ solution | |LabQuest App
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