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AS and A Level: Organic Chemistry
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Five equations you must know for organic chemistry
- 1 Alcohol + carboxylic acid = ester + water (eg CH3OH + CH3CH2COOH becomes CH3OOCH2CH3 + H2O)
- 2 Alkene + hydrogen = alkane (eg CH2=CH2 + H2 becomes CH3CH3)
- 3 Alkene + water = alcohol (eg CH2=CH2 + H2O becomes CH3CH2OH)
- 4 Halogenoalkane + hydroxide ion = alcohol + halide ion (eg CH3Br + OH- becomes CH3OH + Br-)
- 5 Alkene + hydrogen bromide = halogenoalkane (eg CH2=CH2 + HBr becomes CH3CH2Br)
Five facts about alcohols
- 1 Primary alcohols are oxidised into aldehydes and water, which are then oxidised into carboxylic acids. Secondary alcohols are oxidised into ketones and water. Tertiary alcohols cannot be oxidised.
- 2 Alcohols are oxidised by acidified potassium dichromate (H+/K2Cr2O7). This starts off orange and will turn green if it oxidises something (so with tertiary alcohols it will stay orange).
- 3 There are two ways of making alcohols: fermentation and hydration of alkenes. Fermentation is good because it uses renewable resources and does not take much energy, however it can only produce alcohol up to 14% before the yeast die.
- 4 Alcohols are soluble in water as they can make hydrogen bonds with the water. However, the “carbon chain” attached to the OH cannot interact with water and is insoluble. This means that alcohols become more insoluble the longer the carbon chain.
- 5 Alcohols have a very high melting and boiling point compared to alkanes of the same chain length. This is because they can form strong hydrogen bonds with each other that require a lot of energy to break.
Five facts about hydrocarbons
- 1 The longer the carbon chain the higher the higher the boiling point, as there will be more points of contact and stronger van der Waals forces.
- 2 The more branched the carbon chain the lower the boiling point, as the molecules will not be able to pack as close together and will have weaker van der Waals forces.
- 3 Hydrocarbons are insoluble in water as they cannot make intermolecular forces with them.
- 4 Hydrocarbons have low boiling and melting points as the only intermolecular forces that can hold them together are weak van der Waals forces which require little energy to break.
- 5 When processing crude oil (a hydrocarbon), the aim of the game is to get short, highly branched hydrocarbons. This will increase their volatility and make them a better fuel. We do this through: fractional distillation (sorts them into different sizes), cracking (splits long chains into short chains), isomerisation and reforming (makes the chains branched and cyclic).
Cellulose nitrate was then produced by reacting cellulose with nitric acid and sulphuric acid. This did not produce smoke when it exploded so the visibility on battlefields was improved. A fuse wasn't needed as cellulose nitrate could be ignited by percussion, and larger quantities could be used. To use as an explosive cellulose trinitrate and nitro-glycerine were mixed together. Propanone was then used to produce a jelly-like substance out of the mixture. This jelly can be squeezed through holes to produce cords which is why it is called a propellant. The next explosive produced was nitro-glycerine which is produced by heating glycerine with concentrated nitric acid using sulphuric acid as a catalyst.
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OBSERVATIONS: A colour change to colourless indicates an alkene, any other colour change shows Alcohol, aldehyde, ketone, carboxylic acid, ester or phenol. 2. Test unknown with universal indicator. THEROY: universal indicator is a mixed indicator, several indicators with different pH values. When added to different solutions of different pH different indicators change colour, the colour you see is a result of the different indicators mixing together. The colours have been recorded and linked to a colour chart. EQUITMENT: universal indicator, Pipette, Test tube.
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= -420 J AVG = -455 J moles = mass 2.5 = 0.025 molar mass 100 ?H1 = -18.22 units = kJ/mol ?H2 The Reaction between CaO + HCL J = m.c. ?T is used to calculate the energy produced using heat capacity of HCL, and 50ml of HCL with the temperature change in the reaction. J = m.c. ?T 50 x 4.2 x 10.5 = -2205 J 50 x 4.2 x 10 = -2100 J 50 x 4.2 x 9 = -1890 J AVG = -2065 J moles = mass 1.4 = 0.025 molar mass 56 ?H2 = -82.6
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This is because an oxidation reaction was taking place. The dichromate got reduced to form chromium ions and the ethanol got oxidised. It was a redox reaction because electrons were both lost and gained. * As I slowly added the sodium dichromate to the sulphuric acid I recorded that the solution started to bubble, this also showed me that a reaction was taking place * Furthermore as I was adding the sodium dichromate to the sulphuric acid I noticed that when touching the pear shaped flask it was warm.
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3. Anti-bumping granules were added into a water bath. The beaker containing the acid mixture was put into the boiling water bath. 4. The beaker was removed from the water bath 5 minutes after solids were found to form in the mixture. 5. The beaker was cooled by putting the beaker into an ice bath. 6. The reaction mixture were filtered by suction using the following set-up: 7. After a few minutes, the suction was stopped by removing the Buchner funnel from the flask. 8. The residue was soaked with water, and the suction was resumed for a few more minutes.
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7. Further experiment comparisons- to provide addition chemical tests data that are necessary to complete and confirm the identification. Methodology: First of all, the physical state, color, size and shape and odor of the unknown compound G were recorded. Secondly, ignition test and solubility test were carried out. Then sodium fusion test was carried out to prepare the "fusion" solution, followed by the test for the presence of nitrogen and halogens. Afterwards, a serious of chemical characterization tests were carried out. Finally, an IR spectrum of the unknown sample G was obtained for the presence of functional group. Data and Results: Sample G was toxic and flammable.
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* Gas Syringe (100cm3) - To measure out volume of gas. * Chemicals: Powdered copper carbonate3 CuCO3, used as a paint pigment, varnish pigment, seed treatment fungicide and in animal and poultry feed. Plan of action: This experiment is designed to find out which equation is the correct one. It makes use of the fact that each equation states that copper carbonate produces a different number of moles of gas when heated. A known mass of copper carbonate will be heated, and the volume of gas given off will be measured.
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Ethanol * Highly flammable above 13�C causing a narcotic effect if inhalation of the vapour occurs. * Toxic Sodium Dichromate * Very Toxic � Cause cancer if inhaled * Harmful if swallowed * Harmful if in contact with skin * Danger to environment - Very to toxic to aquatic environment may * Cause long-term adverse effects Sulphuric Acid * Very corrosive - cause severe burns * Dangerous with - Sodium, dangerous reactions can take place Water, Vigorous reactions when the concentrated acid is diluted Universal Indicator * Contains several ingredients which are flammable, so it must be kept away from flames.
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The hazards are as follows: Hydrochloric acid - Very corrosive, irritant. Limewater (alkali) - Irritant. Phenolphthalein Indicator - May cause irritation of the respiratory and digestive tract if ingested. Can also cause CANCER. Now, to perform the titration the first thing that needs to be done is to dilute the HCL to a suitable concentration. To do this you will need the pipette and the pipette filler to collect exactly 25ml of HCL (making sure that the level of the 25ml line is at the bottom of the meniscus). Then to place this into a volumetric flask and topping it up to 250ml with distilled water and then to turn the volumetric flask up & down rather than shaking.
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The stored energy of the reactants is higher than the stored energy of the reaction. The difference in energy is released to the surroundings when the fuel and oxygen react. CH3OH + 1.5O2 CO2 + 2H2O METHANOL CH3CH 2 CH 2 CH 2 CH 2 CH 2OH+ 9O2 6CO2 + 7H2O HEXAN-1-OL As seen above in methanol only 1CO2 and 2H2O have been formed, which is a lot smaller than the new bonds formed in hexan-1-ol, 6CO2 and 7H2O are formed and energy released from these are greater and make the reaction more exothermic. 1 I have completed a preliminary test in my module developing fuels as an activity 1.2.
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The aim of this investigation is to analyse mummion, which is an inorganic solid that is obtained from dried up lake beds.
lab coat to protect yourself Inform teacher and seek medical help Water Can spill when pouring into conical flask Clean up any spillages to avoid someone slipping Wipe all spillages. Do not leave spillages unattended Make sure to wear lab coat and safety goggles throughout the whole experiment. Apparatus: * Mummion(5g) * Electronic weighing balance * Conical flask * Distilled water * Evaporating basin * Bunsen burner * Tripod * Heatproof mat * Filter paper * Beaker * Buchner funnel Justification of apparatus: Equipment/chemicals Quantity Justification Electronic weighing balance X1 To accurately measure 5g of the mummion Mummion 5g To
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The diagram shows direct and indirect routes: CH3OH(l) + 1.5O2(g) --> CO2(g) + 2H2O CH3OH(l) + 1.5O2(g) CO2(g) + 2H2O C(g) + 4H(g) + 4O(g) The Hess's law states that the total enthalpy change of combustion for indirect route and the total enthalpy change of combustion of the direct route are the same. Therefore this should mean that: H1 = H3 - H2 Standard bond enthalpies for elements in their gaseous states (kJmol-1): Carbon - Carbon (C-C) = +347 Carbon - Hydrogen (C-H) = +413 Oxygen - Hydrogen (O-H)
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So now that I know the strength of my reactants I am able to choose an indicator. In past neutralisation reaction when and acid has been run into a base with universal indicator the endpoint it when the solution turns greend however. The endpoint is actually: "when you mix the two solutions together in exactly equation proportions. That particular mixture is known as the equivalence point"3 Now I am able to use a pH curve which is simply a graph of pH of an alkali against the volume of acid added. By using a pH curve representing a strong acid and weak base (see left4).
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Phenol molecules form hydrogen bonds resulting into white crystalline solid. When aqueous bromine reacts with a phenol molecule, the hydrogen atoms in the phenol are substituted by the bromine atoms. Thus the final product is 2,4,6-tribromophenol. The reason this reaction is a tri-substitution is because of the OH group in the phenol. It releases electrons onto the aromatic ring in the phenol. This activates the ring allowing it to be more reactive to electrophiles. This is one of the fundamental differences between Benzene and Phenol.
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When heating calcium carbonate carbon dioxide gas is released; this gas will go down the tube to the solutions. If the solution is calcium hydroxide, the carbon dioxide will react with it leaving a milky white precipitate. Equations: CaOH(aq) + CO(g)--> CaCO(aq) + H0(l) Word Count: 134 Ethanoic acid: Apparatus: Solutions A to E Ethanol Concentrated Sulphuric acid Bunsen Burner Stand Water supply Round bottom flask Condenser Tubes Diagram: Method: I will set up the apparatus as shown above. Warming ethanol with ethanoic acid, and a strong acid catalyst (concentrated sulphuric acid), it forms an ester. The O-H bond in ethanol is broken in the esterification reaction.
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For a positive result, bromine water will decolourise and white precipitate forms, this indicates phenol is present. If no positive test is observed, proceed to the next test. Risk assessment before carrying out the test for aldehyde and ketone: Procedure / Chemical Risk Precaution Information derived from 2,4-dinitophenylhydrazine Explosive: risk of explosion by shock, friction, fire, or other source of ignition. Toxic: by inhalation or if swallowed. And it's very toxic to skin. Skin stain yellow on contact with which may be followed by dermatitis. If swallowed, wash out mouth and drink a glass or two of water.
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Furthermore, the theorem also dictates that one mole of any gas at room temperature and pressure occupies 24dm3. So in the first equation, two moles of copper carbonate is needed to produce one mole of cuprous oxide, two mole of carbon dioxide and half a mole of oxygen gas. In the second equation, one mole copper carbonate is needed to produce one mole of cupric oxide and one mole of carbon dioxide. I will also be using the theory of relative atomic mass (RAM)
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Fall in temperature for complete reaction: 25-14=11 = 11C, Mass= 30g, C= 4.18Jg-1K-1 H1= MxCx T =30x4.18x (+11) = 1379.4J/1000 = 1.3794J Number of moles of acid = (30/100) x2 = 0.06 moles in excess Molar mass of potassium hydrogen carbonate Mr= 39.1+1.0+12.0+48 = 100g mol-1 Number of moles= m/Mr = 4/100 = 0.04 mol H for 1 mole= 1.3794KJ/0.04 = 34.49KJmol-1 Experiment 2: Mass of weighing bottle and magnesium carbonate: 20.75g Mass of weighing bottle: 8.75g Mass of magnesium carbonate: 2.00g Time(min) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Temperature(C)
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To do this experiment I will need to use the apparatus shown in the picture below. Note the tubing is to allow the contents of the ignition tube to come out and react with the sulphuric acid. The chemical equation for this reaction is Mg + H2SO4 --> MgSO4 + H2 From this reaction I will be measuring the amount of H2 that is being produced, I expect that to be around 70cm3 seeing as the gas syringe can hold up to 100cm3. To calculate how many moles of hydrogen I have collected I must use the rule that any gas is 24dm3 Firstly I must convert the cm3 --> dm3 by dividing 70 by 1000 70 � 1000 = 0.07dm3 Secondly I need to divide the 0.07dm3 by the 24 litres using the rule.
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In chemistry alcohol refers to the complete homologous series, of alcohols of which ethanol is just one. Alcohols consist of an hydroxyl group covalently bonded to an alkyl or cycloalkyl chain. The hydroxyl, is the OH group, is the functional group. Alcohols can be classified as primary, secondary or tertiary depending on the number of carbon atoms attached to the carbon atom with the hydroxyl group. The alcohols I am using are all primary, meaning that they have one carbon atom attached to the carbon with the hydroxyl group.
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For a titration between and weak acid and a strong alkali, phenolphthalein is used as the indicator. For a titration between a strong acid and strong alkali, either methyl orange or phenolphthalein can be used as the indicator, although methyl orange is usually used. For a titration between weak acid and a weak alkali, no indicator is suitable, and a pH meter, conductivity meter or temperature probe has to be used. Given this information I can work out that methyl orange will be the most suitable indicator to use because we are using sulphuric acid, being a strong acid and sodium carbonate, being a weak alkali.
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A higher wick would mean different amounts of energy being released each time, creating an unfair test. Chemical Theory This task mainly focuses on the making and breaking of bonds. To combust a fuel, chemical bonds are broken in the reactants and new chemical bonds are formed to make products. Breaking bonds between atoms is endothermic (energy is absorbed from the surroundings), and making bonds between atoms is exothermic (energy is given out to the surroundings). It is as a result of these processes whether a reaction is overall endothermic or exothermic. The enthalpy change of combustion of a certain fuel depends on the number of bonds there is to be broken, which is dependable on the size of the molecule involved.
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Vitamin C. The objective of this project is the determination of the amount of vitamin C in drinks. The investigation helps us know which brand and which type of fruit drink contains more vitamin C.
The result may give an indication to us in choosing the suitable fruit drink for ourselves. DCPIP is an oxidizing agent which can oxidize Vitamin C (Ascorbic acid). By titrating the selected drinks with standardized DCPIP solution, the amount of the vitamin C content in each drink can be determined. The Vitamin C content of five types of fruit juice of two brands, Hi-C and Vita, will be analysed. The result will then be compared and interpreted. Content Abstract----------------P.4 Objectives---------------P.6 Experiment-------------P.7 Conclusion--------------P.14 Reference----------------P.15 Objectives Through this project, we would like to find 1. the content of the vitamin C in the Vita and Hi-C Corporation of different types of fruit drink; 2.
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This tells us that (A) must be a ketone- had (A) been an aldehyde, a "silver mirror" would have been formed on the test tube. This is because Tollen's reagent ( [Ag(NH3)2]+ ) is reduced upon heating with aldehydes, forming silver metal. From these data, I believe (A) to be a ketone. However, this must be confirmed by the use of the spectra. On the NMR spectrum, there is a single peak at 2.2 ppm. This has a relative peak area of 6. This suggests 6 protons in a (fig 1)
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