with the oxidation of ascorbic acid by iodine. Iodine is relatively insoluble‚ but this can be improved by complexing the iodine with iodide to form triiodide: I2 + I- I3- Triiodide oxidizes vitamin C to form dehydroascorbic acid: C6H8O6 + I3- + H2O --> C6H6O6 + 3I- + 2H+ As long as vitamin C is present in the solution‚ the triiodide is converted to the iodide ion very quickly. Howevever‚ when the all the vitamin C is oxidized‚ iodine and triiodide will be present‚ which react with starch to form
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protonated OH group is a good leaving group. Step 1: CH3 CH3-C-CH3 + H+ HO CH3 CH3-C-CH3 H2O+ Fast u u In the second step‚ water molecule is lost with the formation of a carbonium ion. This is the rate determining step. CH3 CH3 u Step 2: Slow CH3-C-CH3 CH3-C-CH3 + H2O + H2O+ In the final step carbonium ion loses proton from its adjacent carbon atom which results in more stable alkene. The anions of the acid or another alcohol molecule will function as a base and facilitate loss of proton.
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HKDSE CHEMISTRY – A Modern View (Chemistry) Coursebook 3 Suggested answers |Chapter 25 Simple molecular substances with non-octet |Page Number | |structures and shapes of simple molecules | | |Class Practice |1 | |Chapter Exercise
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ability to easily bind with calcium and magnesium ions. EDTA and Ca2+ react at the ratio of 1:1. The purpose of this experiment is to determine the hardness of water by measuring the concentrations of calcium and magnesium in water samples by titration. The total hardness is expressed in terms of the equivalent concentration of calcium carbonate in parts per million. The amount of CaCO3‚ in this experiment‚ is determined by titrating calcium ions from a sample tap water (from Baguio). Water
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these are exactly the opposite of the oxygen definitions. For example‚ ethanol can be oxidised to ethanal: [pic] You would need to use an oxidising agent to remove the hydrogen from the ethanol. A commonly used oxidising agent is potassium dichromate(VI) solution acidified with dilute sulphuric acid. [pic] Note: The equation for this is rather complicated for this introductory page. If you are interested‚ you will find a similar example (ethanol to ethanoic acid) on the page dealing with writing
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Thermochromism Thermochromism refers to the phenomenon of color changes by the agency of heat. Obviously‚ the color changes are made possible by the temperature-induced chemical or physical changes of materials incorporated into the inks. Sometimes‚ the color change occurring at a temperature is permanent‚ and at other times the original color can be regained on cooling. Accordingly‚ we have an irreversible or reversible thermochromic system. The required chemistry can be adopted based
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What are the exceptions? Sodium chloride‚ sodium iodide‚ and sodium sulfates generally do not form precipitates. One exception in our results with all three of these was when they were each combined with Fe(NO3)3 (iron nitrate) in which all three yielded brown precipitates. E - Which cations generally
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Name: |Date:| Exp 1: Observations of Chemical Changes|Lab Section: | Data Tables: Part 1: |Chemicals|Well No.|Observations of the Reaction| A.|NaHCO3 + HCl| H12|White and bubbled slightly and settled down to smaller smaller bubbles| B.|HCl + BTB| H11|Golden yellow; looked darker under the black paper| C.|NH3 + BTB|H10 |Dark blue| D.|HCl + blue dye| H9|Greenish color| E.|Blue dye + NaOCl| H8|Blue and lighter than NH3+BTB solution color| | with the 1 drop of HCl| H8|Turned blue green
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HKDSE CHEMISTRY – A Modern View (Chemistry) Coursebook 3 Suggested answers Chapter 25 Simple molecular substances with non-octet structures and shapes of simple molecules Page Number Class Practice 1 Chapter Exercise 2 Chapter 26 Bond polarity Class Practice 4 Chapter Exercise 5 Chapter 27 Intermolecular forces Class Practice 7 Chapter Exercise 9 Chapter 28 Structures and properties of molecular crystals Class Practice 11 Chapter Exercise 12 Part Exercise 14 Chapter 29 Chemical cells in daily life
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CONTENT INTRODUCTION WATER PURIFICATION BY NANOPARTICLES NANOPARTICLES IN WASTE WATER TREATMENT MATERIALS AND METHODS CONCLUSION REFERENCES INTRODUCTION WATER PURIFICATION: It is the process of removing undesirable chemicals‚ biological contaminants‚ suspended solids and gases from contaminated water. NEED: The goal of this process is to produce water fit for a specific purpose
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