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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).
* Finally weigh the burner again * Record result in a table. Results Mass (Before) (g) Mass (After) (g) Change in Mass (g) Temperature (Before) (oC) Temperature (After) (oC) Change in Temperature (oC) 24.68 23.84 0.84 20.4 40 -19.6 23.64 22.24 1.4 52 64 -12 22.24 22.00 0.24 64 69 -5 22.00 21.59 0.41 69 72 -3 21.59 21.39 0.2 72 74 -2 AVERAGE 22.83 22.212 0.618 55.48 63.8 -8.32 Below is the equation for the reaction i carried out: CH3OH + (11/2)
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This method is now days still used to purify the water. After 1500 BC Egyptians used the coagulation process which is a process where in solids in water are separated, the water is than filtered with a filter bag. The coagulation method was used till 1845 AC. In 1845 British scientist John Snow discovered that Chlorine works as a good purifier of water. John Sow was the first scientist who's water treatment worked well and led to governments starting to install municipal water filters and hence the first government regulation of public water.
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1897, Germany, Elberfeld - Felix Hoffmann, at Bayer pharmaceuticals, chemically synthesizes a stable form of ASA powder that relieves his father's rheumatism. The compound later becomes the active ingredient in aspirin named - "a" from acetyl, "spir" from the spirea plant (which yields salicin) and "in," a common suffix for medications. So from that day forth acetylsalicylic acid became known as aspirin which did not have the unpleasant side effects that salicylic acid caused. 1899 - Bayer distributes aspirin powder to physicians to give to their patients.
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--> 2H2O (l) + O2 (g) Hydrogen Peroxide is also broken down by inorganic catalysts such as Manganese (IV) Oxide- MnO2 (s) + 2H2O2 (aq) --> MnO2 (s) + O2 (g) + 2H2O (l) The type of catalysts that I am going to be using in this decomposition reaction are- Heterogeneous- is where the catalyst is in a different phase to the reactants. The Hydrogen Peroxide solution is in a aqueous state and the Manganese(IV) Oxide catalyst is in a solid state. 2 For a successful collision to occurs the particles have to collide at enough energy for the reaction to occur, only a fraction of the particles have enough energy for the reaction to occur.
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One of the most fundamental scientific laws states that energy is conserved and that the total quantity stays constant. It cannot be created or destroyed. (4) The understanding of this system to which the solar energy is captured, converted, stored and moved is what lead to the significant evolution of the human race. (4) After the discovery of fire and burning trees for energy, humans stopped wandering, hunting and gathering food, but began to grow food instead, leading to agriculture and the beginning of civilization. (4) Human population growth was relatively slow for most of human history but within the past 500 years the advances made in the industrial revolution have helped build an enormous rise.
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In order to get this ratio, you would have to use equal volumes of the two gases. Because water is cheap, it would seem sensible to use an excess of steam in order to move the position of equilibrium to the right according to Le Chatelier's Principle. In practice, an excess of ethene is used. This is very surprising at first sight. Even if the reaction was one-way, you couldn't possibly convert all the ethene into ethanol. There isn't enough steam to react with it. The reason for this oddity lies with the nature of the catalyst.
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= 63.55+32.07+64 = 159.62 g/mole Molar Mass of all the Waters in Compound: 5H2O = 80+10.10 = 90.10 g/mole Theoretical Percentage of Water in Hydrate: 90.10 * 100 = 36.98% 249.72 Experimental Percentage of Water in Hydrate: .74 * 100 = 30.58% 2.42 Percent Error in the Lab: 36.08 - 30.58 = 15.24% 36.08 Questions: 1)
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Carefully read the directions first 2) Gather Materials - Test tubes, several unknown compounds, conductivity testers, oil, wooden stirring sticks, water, Bunsen burner, test tube racks, goggles. 3) Put on Safety Equipment (goggles) 4) Perform Test One by pressing compounds to see how hard/soft it is 5) List Observations 6) Perform Test Two by getting 4 cups of 20 mL of distilled water 7) Measure out a small quantity of each substance 8) Then put each substance into different cups of water 9) Stir them out 10) Test the conductivity of the compounds using the conductivity testers 11)
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The aim of this experiment is to produce Aspirin. This is an estrification in which an alcohol reacts with an acid and a small molecule is often eliminated. The reaction takes place under a concentrated acid catalyst which speeds up the chemical reaction.
* Gastric ulcers many occur with long term use * Nausea, vomiting, abdominal pain * Dizziness, hallucinations * Seizures * Allergic reaction Complications can be avoided by using the enteric - coated Aspirin which does not dissolve until reaching the intestine. Aim Aspirin is an anti-inflammatory pain killer, which is use world-wide for pain relief. The empirical formula of Aspirin is C9H8O4 The structural formula is (3) The aim of the investigation was to determine the purity of synthesised aspirin, and pure aspirin.
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The smaller the time needed, the faster the rate of hydrolysis. Hydrolysis is a chemical process in which a certain molecule is split into two parts by the addition of a molecule of water. One fragment of the parent molecule gains a hydrogen ion (H+) from the additional water molecule. The other group collects the remaining hydroxyl group (OH-). Types of halogen compound Haloalkanes: organic compounds having one or more halogen atoms replacing hydrogen atoms in alkanes. The general formula of haloalkanes: CnH2n+1X. Classification of haloalkanes: Halobenzenes- organic compounds in which the halogen atom is directly attached to a benzene ring.
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These are reasonable accurate, but due to a lack of the precision demonstrated by the bulb pipettes, they will not be used for measurement. I will use 100 cm� beakers as the environment for my reactions as they are easily accessible, are a suitable size considering the volume of the solutions I will be injecting into them and, as the solutions will already be measured and only need to be mixed when in the beaker, they do not have to be particularly accurate.
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The test tubes were shaked and the order in which the precipitates appeared was observed. The precipitate formed in each case was noted. B: 1. 2cm3 of ethanol were added to two separate test tubes and were placed them in a beaker of water kept at about 60?. 2. 1 cm3 of 0.1M silver nitrate(V)solution was added to each test tubes. 3. Using separate teat pipettes, 5 drops of 1-bromobutane was added to the first test tube, 5 drops of bromobenzene was added to the second.
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3. Mixture from #2 + 0.5 g .............. - The solution turns cloudy. trisodium phosphate (Na3PO4) DISCUSSION: The scum formation is exist which floats on the surface of the solution when CaCl2 solution, which contains the cation Ca2+, react with soap molecules and contribute to the water hardness. COO- + Ca2+ ........... [COO]2Ca Trisodium phosphate (Na3PO4) solution is added to clean away the scum formation of the Ca2+ and Mg2+ ions by capture and deactivate from the mineral from "hard" water. If not removed, these hard-water ions react with soap and form insoluble deposits. Trisodium phosphate binds to Ca2+ and Mg2+, forming soluble chemical species, called complexes or chelates.
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What is actually observed is different. Instead of reacting, benzene is inert to Br2. If however you present a catalyst (FeBr3) to the reaction, something unusual also occurs. An addition reaction will not occur. Instead, a substitution reaction will take place. This is uncharacteristic of alkenes and is instead usually attributed with alkanes. In addition to this, benzene has another abnormal trait which is not associated with alkenes. The bond lengths in benzene possess a special quality. In another alkene such as cyclohexene, the length of the C-C bonds differ to the length of the C=C bond.
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Apparatus and equipment : 250 cm3 conical flask 3 burette 1 250 cm3 beaker 2 filter funnel 1 25.0 cm3 pipette 1 pipette filler 1 safety spectacle 1 white tile 1 wash bottle 1 250 cm3 volumetric flask 1 100 cm3 beaker 2 dropper 1 heat-proof mat 1 Bunsen burner 1 25 cm3 measuring cylinder 1 9. Procedure : 1. 1.58 g of oxalic acid crystal was weighted accurately which was then dissolved in distilled water. 2. The solution was transferred to volumetric flask and made up to 250 cm3 (the mark)
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My aim is to make an accurate comparison of the enthalpy changes of different alcohols and explain how and why the enthalpy change is affected by its molecular structure.
Many reactions like this are accompanied by a temperature rise; the more bonds there is the more energy needed to break them. However some reactions are accompanied by a fall in temperature. Theses are known as endothermic reactions because heat energy is taken in from the surrounding; more energy is released as more bonds are broken. Reactions are exothermic because more energy is released in making new bonds than used in break the bonds. To work out the enthalpy change in each of the alcohols, I will use the formula mc?t, where: m= mass of the substance heated, c= specific heat capacity of the substance ?T= change in temperature in the substance.
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Ca� + H C-(CH ) -COO �[H C-(CH ) -COO ] Ca� Although a small degree of water hardness is beneficial to health, it can be a problem for hot water boilers or heaters. The formation of Calcium Carbonate precipitates onto the heater coils and reduces its efficiency: (boiler scale) CO� + Ca� � CaCO In this experiment the hardness of an unknown water sample will be determined by titration against EDTA, the anions H EDTA� react with metal ions in aqueous solution on a l:1 ratio. Because of the equilibrium constraints for the reactions are different concentrations of both Ca� and Mg� can be determined individually.
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Typically cows spend about 8 hours eating, 8 hours sleeping and 8 hours chewing their cud. They eat about 40-45 kg of feed each day. In order to get really thick and rich milk, the cow they milk is excreted from must be fed and taken care of. Cows are usually provided with a fresh pack of grass in the morning after milking and another fresh pack grass in the evening after milking. They can also be fed grains or hay but they mostly tend to be fed with products that consist soy. Since soy gives off many nutrients and strength.
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On the other hand, in reaction (3), the HCl added should be in excess to ensure maximum benzoic acid formation. The sign of complete reaction can be told by testing it with wet blue litmus paper, it should turn from blue to red, indicating that the reaction mixture has become acidic. Moreover, since benzoic acid has very low solubility in water, white precipitate would form which can be separated by simple filtration.
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2 Final burette reading (cm3) 15.1 30.2 Initial burette reading (cm3) 0 15.1 Volume of NaOH used (cm3) 15.1 15.1 Titration of final reaction mixture against NaOH Titration 1 (trial) 2 Final burette reading (cm3) 8.2 16.0 Initial burette reading (cm3) 0.0 8.2 Volume of NaOH used (cm3) 8.2 7.8 No. of moles of CH3COOH in 1 cm3 of reaction mixture before heating = [(density x volume) / molar mass] / volume = [(1.05 gcm-3 x 15 cm3) / (12x2+1x4+16x2)] = 8.75 x 10-3 mol 2 NaOH + H2SO4 Na2SO4 + 2 H2O No. of moles of H+ from H2SO4 in 1 cm3 of reaction mixture before heating (8 drops)
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* d. Many synthesis studies of nicotine occurred. * II. The chemistry of nicotine * A. Chemical and Physical Data * a. Density of 1.01 g/cm3 * b. Melting point of 110 F and a boiling point of Boiling point of 477 F * c. Described as a colorless poisonous gas occurring naturally in tobacco. * d. empirical formula of C10H14N2 and has a molar mass of 162.26 g/mol. Half life of about 2 hours and a bioavailability of 20-45% * B. Chemistry * a. Nicotine is soluble in water and non polar.
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Vitamin C. I will investigate whether orange juice contains the most Vitamin C and how I can speed up and slow down the oxidation process of Ascorbic Acid.
DCPIP (blue) + H+ ----------> DCPIPH (pink) DCPIPH (pink) + Vit C ----------> DCPIPH2 (colorless) However I will also be using Iodine as an indicator to see if it is a better one than DCPIP. DCPIP oxidises very easily and therefore it will take more DCPIP to oxidise vitamin C because it is already oxidizing. DCPIP is an oxidizing agent so it will reduce something else e.g. the Ascorbic acid. The amount of ascorbic acid can be determined by a redox titration with a standardised solution of iodine. The iodine is reduced by the ascorbic acid to form iodide. As shown in the other half of this redox equation.
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This means that one mole of sulphuric acid can release two moles of hydrogen ions, H+, when it reacts in aqueous solution. The reaction of sulphuric acid with sodium hydroxide solution forms sodium sulphate solution, in which both of the acidic hydrogen's react with hydroxide ions. 2NaOH(aq) + H2SO4(aq) --> Na2SO4(aq) + 2H2O(l) Method (a): by measurement of the gas Apparatus: -the quantities of chemicals you would use and calculations to show how you decided these quantities. 1. Set up apparatus as shown below.
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Photosynthesis consists of two stages: a series of light- dependent reactions, which are temperature independent and a series of light independent reactions, which are temperature dependent. Increasing light intensity can increase the rate of the light dependent reactions. Increasing the temperature can increase the rate of the light independent reactions. Photosynthesis begins with the absorption of light by pigments. Chlorophyll and other pigments known as carotenoids absorb different wavelengths of light, which broadens the spectrum of light energy that can be fixed through photosynthesis.
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Once you have noticed a blue-black colour that is when you will know there is presence of ascorbic acid in the sample of fruit or vegetable. Plan: Equation for the Reaction: C6H8O6 + C4H4BrNO2 -->C6H6O6 + C4H5NO2 + HBr This equation shows that 1 mole of ascorbic acid will be titrated against 1 mole of N-Bromosuccinimide to make 1 mole of dehydroascorbic acid, succinimide and hydrogen bromide. Indicator: In this experiment the 4% KI and 1% soluble starch will act as indicator.
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