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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).
- Marked by Teachers essays 7
- Peer Reviewed essays 13
Some nations (Australia, USA (Obama)) are reluctant to join because of the impact on their economies.(See Geog notes) The ozone layer The Ozone Layer absorbs much of the harmful ultraviolet radiation emitted by the sun, which, if it were to reach the Earth's surface unimpeded, would cause burning and skin cancer (also vitamin D :)) Ozone, O3 is constantly formed and broken down. An equilibrium with O2 and O* is present. Overall Equation: O3 ? O2 + O O3 + (UV Rad) --> O2 + O* O2 + O* --> O3 These two reactions would maintain a steady rate if undisturbed.
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Once the solution had cooled 3.8g of p-acetamidophenol was added. Through the top of the condenser ethyl iodide (3.0cm3) was introduced to the pale green mixture and the mixture boiled at reflux temperature (20-25�). Ethyl iodide was obtained from a burette in the fume hood few minutes before its use, due to its flammable nature and harmful vapour. A darkening green colouration occurred while p-acetanilide dissolved changing through to brown and then yellow. Once the reflux was completed 40cm3 of water was added and the flask was left in ice for a few minutes to cool.
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As this is a low critical temperature it makes critical carbon dioxide very easy to work with. Another useful feature of critical carbon dioxide is that when it is in its solvent form it is able to be altered by making slight adjustments to temperature and pressure. The phase diagram below of carbon dioxide shows us that its triple point ( where all states of carbon dioxide exist together)
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Adding water to it gives a solution pale grey with green tinge. After dissolving the solutions turns clear with a green-grey colour and no precipitate. Prepare a solution of 6.0g of sodium ethanoate in 25cm3 of water in a conical flask. Sodium ethanoate is a white powder. It dissolves completely in water to give a colourless solution. Carefully add 2cm3 of ethanoic anhydride to the solution of phenylammonium chloride,and stir vigorously until all the ethanoic anhydride is dissolved. Ethanoic Anhydride smells of vinegar. Adding it to the phenylammonium chloride gives a solution with oily blobs with a sweet fruity smell.
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Sodium hydroxide is a caustic soda and so is not very dangerous however regular safety precautions (goggles, labcoats and gloves) and care is still carried out to prevent spillages. Ethanol is highly flammable and dangerous substance as it contains methanol. Therefore, it should not come into direct contact with any flame. It is harmful it swallowed, inhaled or comes into contact with skin. Observations: Methyl benzoate is originally a transparent liquid however the addition of the sodium hydroxide, ethanol and anti bumping granules turns the liquid cloudy.
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* 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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= 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 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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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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Protective clothing. Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention. Eyes Redness. Face shield, or eye protection in combination with breathing protection. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor. Ingestion ( Cough. Sore throat. Blue lips or finger nails. Blue skin. Confusion. Convulsions. Dizziness. Headache. Nausea. Unconsciousness. Do not eat, drink, or smoke during work. Wash hands before eating. Rinse mouth. Induce vomiting (ONLY IN CONSCIOUS PERSONS!). Refer for medical attention. See Notes. Ethanoic anhydride/Acetic anhydride TYPES OF HAZARD / EXPOSURE ACUTE HAZARDS / SYMPTOMS PREVENTION FIRST AID / FIRE FIGHTING FIRE Flammable.
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Glucose is gradually broken down in this process and energy is released. Hydrogen is also released in a process called oxidation, and when hydrogen is released the resazurin gains this hydrogen. The gaining of hydrogen is called "reduction" and molecules which gain this hydrogen are said to be reduced. I think that this will happen faster in my experiment when there is less distilled water in each yeast suspension. We did two experiments. One to measure the optimum temperature to use the water bath for the yeast to react, and one to determine the best amount of resazurin dye to use.
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Solubility in water: (a) a little phenol (b) a lot of phenol phenol dissolves gradually on shaking / insoluble, phenol forms oil-like droplets on shaking (soluble when heated) pH of solution universal indicator changes from green to orange, i.e. acidic Reaction with NaHCO3 phenol becomes insoluble after adding NaHCO3 and forms a emulsion on shaking Reaction with NaOH Solubility of phenol in NaOH is much higher than in water. After adding conc. HCl, phenol becomes insoluble (appear as droplets) again. Reaction with Na Na floats and evolves a colourless gas, which has a 'pop' sound on burning splint test, gradually (but faster than in ethanol)
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measuring cylinder, and was then added into a conical flask as follows : Student pair A B C D Volume of propanone solution (V1) / cm3 25.0 20.0 15.0 10.0 Volume of distilled water (V2) / cm3 0.0 5.0 10.0 15.0 � 50 cm3 of iodine solution was added to the propanone mixture as quickly as possible and at the same time the stop-watch was started. The contents were mixed. � After 5 minutes, 10 cm3 of the reaction mixture was pipetted into another conical flask containing 10 cm3 of the sodium hydrogencarbonate solution (it was measured during the 5 minutes interval), the time was noted at which this was done.
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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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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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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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