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GCSE: Organic Chemistry
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This is because there is more surface area and so the hydrochloric acid will react with it with more ease and speed. Throughout my investigation in preliminary work 1 there have been several problems. Firstly collecting the 50cm3 of hydrogen was hard as I was not sure of when to stop the stop clock and whether my readings were accurate or not as I feel I have a slower reaction time than others, also I was not definite that the measuring tube was completely filled with water which could have given me erroneous results as I found it difficult to handle and struggled on my own.
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It is also used in dyeing, tanning, fire proofing textiles, vegetable glues and baking powder (Orica Watercare, 2008). An ionic lattice is a structure of millions of atomic formations of an ionic substance like buildings into one 3-D formation. The molecules are positioned orderly with a repetitive arrangement. In an ionic crystal lattice structure, the anions are mostly larger than the cations where the anions form crystal array and the cations reside in holds between the anions. Many different kinds of ionic lattices and patterns depend on the complexity of the molecules.
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This is because of its relatively low price when compared to the other fuels. Buntanol is the fourth largest molecule - and as such it provides more energy (27.10 KJ/g) and at the lowest price (�6.10) than any of the others specified. To measure the energy expelled by each of the fuels, the following formula was used: Mass x Specific Heat Capacity X Temperature Rise = Heat Energy Gained (kg) (J/KgoC) (oC) (J) Specific heat capacity is the measure of the heat energy required to raise the temperature of a specific quantity of a substance by one Kelvin.
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Preliminary work Reaction of a metal and acid 2HCl + Mg MgCl2 + H2 Bubbles of hydrogen are produced until all the magnesium has reacted The test for hydrogen is a lighted splint gives out a sort of pop noise. We decided not to use this experiment as there are too many variables such as trying to count all of the bubbles that are produced from the reaction it is also hard to cut the exact same amount of magnesium for each test so we decided not to use this experiment.
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Why have farmers in the present time relied on use of artificial fertilizers rather than organic fertilizers? Plants need numerous different chemical elements in order to grow and thrive. The biogenic chemical elements which are particularly important for the growth of plants are nitrogen, phosphorous and potassium, and they are needed in large quantities (see Appendix A). However in reality as generally they accumulate in soils in the process of microorganisms decomposing dead of plants and wastes of animals sources of these macronutrients are limited naturally, so their availability in soils tends to be so low that they can become deficient very often due to the difficulty of natural replacement.
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Investigation to compare quantitatively the concentration of reducing sugars in samples of fresh orange, lemon and grapefruit juice
The differences in colour mean that the Benedict's test is semi-quantitative, i.e. it can be used to estimate the approximate amount of reducing sugar in a sample. First of all, a range of colour standards is produced by preparing a series of glucose solutions of known concentrations. To an equal volume of each is added the same volume of Benedict's reagent and they are then heated in a water bath for the same length of time before being cooled to room temperature. An equal volume of an unknown sample is then treated in the same way and the colour compared with that of the colour standards.
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The experiment would be unreliable and discredited. For example, a larger or small flame size will heat the water more or less, in the same time period, or the volume of water can change the temperature increase, as more or less molecules will need to be heated. Method * Weigh spirit burner * Measure 50cm3 of water in the measuring cylinder * Pour water into a copper beaker * Take water temperature * Place beaker into clamp, 15.5cm above the surface * Place spirit burner under the beaker and light the wick * (NOTE-The flame size should be about the same in each experiment.
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Fossil fuels are a non-renewable energy resource and will eventually run out. Fossil Fuels contain the products of photosynthesis of plants from millions of years ago but have lost much of their oxygen and are found as hydrocarbons. The Green House effect. Today scientists are concerned about global warming. The Earth and its atmosphere act like a green house - light from the sun hits the planet and changes into heat. The atmosphere surrounding the earth acts very much similar to the glass surrounding a green house with light passing through the atmosphere but not being able to leave as with a greenhouse.
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I have shown this information in a table below. Bond Energy released/required O-O +/-496 C-H +/-412 O-H +/-463 C-C +/-348 C-O +/-360 Alcohol Balanced Equations Methanol CH3OH+1.5O2=CO2+2H2O Ethanol CH3CH2OH+3O2 =2CO2+3H2O Propanol CH3CH2CH2OH+4.5O2 =3CO2+4H2O Butanol CH3CH2CH2CH2OH+6O2 =4CO2+5H2O Pentanol CH3CH2CH2CH2CH2OH+7.5O2 =5CO2+6H2O Alcohol Bonds Energy released when bonds are broken Energy needed to reform Total energy transfer Methanol C-H x 3 C-O x 1 O-H x 1 O-O x 1.5 +2803 -2572 231 KJ/mol Ethanol C-H x 5 C-C x 1 C-O x 1 O-H x 1 O-O x 3 +4719 -4218 501 KJ/mol Propanol O-O x 4.5 C-H x 7 O-H x 1 C-C x 2 C-O x 1 +6635 -5864
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If we only use a small volume of water the heat energy from the spirit burner will give the water molecules energy faster as there are will less of them so more heat energy per molecule, this means the bonds will loosen and break quicker so the reaction will be faster. * Distance between spirit burner and Copper Calorimeter: The further the copper calorimeter is from the heat source the more heat will be lost into the surrounding atmosphere and not directed towards the water and the slower the reaction will be.
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That option may be a little off putting because many drunken people and tramps end up there. So you�re itinerary for the coming five days, what should you choose, where should you go? A whole day, if not more, should definitely be spent at Brent Cross shopping centre. It offers everything you could want, from food, to hairdressing salons and not to mention the rather expensive labels to the electronic gismos at Gadgetshop! At the moment there is a funfair opposite the centre, very promising for little kids with many merry go rounds, but if you are more daring there are only 2 scary rides with rip off prices.
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H2O Pentanol 3- The Tools That I Used Are: * 5 spirit burners; each one containing one of the five alcohols ethanol, methanol, propanol, pentanol and butanol. * A empty can of any fizzy dink, but it should have thin walls. * Thermometer. * Accurate electronic balance. * Matches. * Measuring cylinder for make accurate volume of water (volume of water = 200 cm3). 4- The used apparatus: 5- Procedure: 1) Wash the can, dry it by tissue paper, measure it by the electronic balance and record the reading.
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He died there the following year. Aristotle, like Plato, used his dialogue in his beginning years at the Academy. Apart from a few fragments in the works of later writers, his dialogues have been wholly lost. Aristotle also wrote some short technical writings, including a dictionary of philosophic terms and a summary of the "doctrines of Pythagoras" (the guy from the Pythagorean Theorem). Of these, only a few short pieces have survived. Still in good shape, though, are Aristotle's lecture notes for carefully outlined courses treating almost every type of knowledge and art.
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Find out the heat of combustion in the five fuels; Methanol, Ethanol, Propanol, Butanol, Pentanol, All of these alcohols are apart of the Hydrocarbon chain.
To make sure I have exactly 30 cubic centimetres in the cylinder I have to get down on my knee and get my eye sight level to the mark which is labelled "30cc" to get the experiment as accurate and reliable as I can. When I am satisfied with how much water I have got in the cylinder, I will pour it in the boiling tube and record the temperature of it. I will next put my goggles on to protect my eyes and light the Bunsen burner, then I will light one end of the taper by putting it in the Bunsen burner flame.
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NECAR3, the first commercially available fuel cell vehicle was introduced by Diamler-Benz of Germany. General Motors, Ford and Ballard Power Systems(Canada) too are putting up stiff resistance. Types of Fuel Cells: Broadly Fuel Cells are classified as: 1. Polymer Exchange Membrane Fuel Cell (PEMFC) 2. Molten Carbonate Fuel Cell (MCFC) 3. Solid Oxide Fuel Cell (SOFC) 4. Phosphoric Acid Fuel Cell (PAFC) 5. Direct Methanol Fuel Cell (DMFC) 6. Alkaline Fuel Cell (AFC) 7. Protonic Ceramic Fuel Cell (PCFC) Comparison of General Types of Fuel Cells Type PAFC MCFC SOFC PEMFC Electrolyte Phosphoric Acid Alkali Metal Carbonates Stabilized Zirconium Oxide Polymer Exchange Membrane (Teflon /Nafion )
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CALCULATIONS: METHANOL: (C-H) x3 = 435 x 3 Energy input (O-H) x1 = 464 (C-O) x1 = 358 (O=O) x1.5 = 497 x 1.5 total = 2872.5 Energy output (C=O) x2 = 803 x 2 (H-O) x4 = 464 x 4 total = 3462 DIFFERENCE = -589.5 ETHANOL: (C-H) x5 = 435 x 5 Energy input (O-H) x1 = 464 (C-O) x1 = 358 (C-C) x1 = 347 (O=O) x3 = 497 x 3 total = 4835 Energy output (C=O) x4 = 803 x 4 (H-O)
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However more product will be formed and so more energy will be released. A fuel usually gives an exothermic reaction. This is when more energy is released through making bonds then breaking them. A good fuel has the greatest difference in energy released so energy needed to make bonds is less then energy needed to break bonds. Ethanol's is a mixture of carbon, hydrogen and oxygen and its chemical formula is C2H5OH. Ethanol does not have many bonds to break so will take a relatively small amount of energy to burn effectively.
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How Does The Increase In The Length Of The Carbon Chain Affect The Energy Produced When Different Alcohol's Are Burnt.
* Temperature rise * Size of carbon chain. The factor, which I will be investigating into, will be the size of the carbon chain. The other factors will be controlled to ensure the investigation remains a fair test. In the preliminary work, it was tested that 100cm� of water was not enough water to cover the bottom of the thermometer but 300cm� was too much and it took too long for that amount to rise a sufficiently. So 200cm� was tested and it was decided that would be the most suitable amount to use.
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O H O H O H O H C When new bonds are made energy is given out. This reaction is called EXOTHERMIC. H= Delta H is the energy change Calculating energy when new bonds are made 2 (C=O) + 4 (H - O - H) New Bonds C = O x 4= 740 x 4= 2960 H = (5570) + (- 6672) H - O x 8= 464 x 8=3712 = 5570 - 6672 = -1102 kj/mol -6672 H = -1102 = -551kj/mol Calculate H for Methanol, Ethanol, Propanol and Butanol.
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We shall use a thermometer to measure this heat change. The flame of the alcohol burner must be blown out after the original temperature of the water has increased by 40�C. The metal beaker shall be held at the same distance above the alcohol burner each time by a clamp attached to a stand, and another clamp shall hold the thermometer in the water in the beaker. The alcohol burner shall be weighed before and after the experiment on electronic scales accurate to hundredths of grams. The difference in weight shall be calculated each time.
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Method To carry out this investigation, I started by placing all bags, coats and stools away from working areas and placed under desks. Lab coats and goggles were then put on, to ensure that there was no danger of injury, and then the above listed apparatus was collected. One heatproof mat was placed near a gas tap so that a Bunsen burner could be placed on it, in order to light the splints. Then a fuel burner was placed on a heatproof mat, and it was shielded by placing four heatproof mats around the burner, with the mats secured together using parcel tape.
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The only thing that changes the alcohols is the number of these molecules so alcohols like Ethanol, which is C2H5OH, should burn not nearly as well as Octan-1-ol, which is C8H17OH because Octan-1-ol has more molecules. The number of molecules is directly proportional to the amount of heat produced when burnt because the more bonds are broken by heat the more the more energy given off when they are broken. In Physics I have learnt about the transfer of energy and formulae for calculating the amount of energy given off by a reaction.
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If net bond breaking > net bond making then the reaction is endothermic. If the net bond making > net bond breaking then the reaction is exothermic. Therefore in an exothermic reaction the products are at a lower energy level than the reactants, because there is more energy given off when bonds are made then broken. The excess energy is given off as heat. The reaction needs a spark or burning splint to light the flame to supply the activation energy.
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In this investigation I will be burning alcohols to heat up a beaker of water. I will be burning five alcohols, methanol, ethanol, propanol, butanol and pentanol. The aim is to find out how much energy is produced when burning these alcohols.
The bond that are formed in an exothermic reaction can be of two types. The first could be ionic, where a metal is produced. Ionic bonding involves electrons transferring from one atom to the other consequently leaving an electrostatic force between them. The other form of bonding is covalent where atoms share electrons to complete their outer orbit. An example being Methane where four hydrogen atoms each share an electron with a carbon atom. essaybank.co.uk The method that I will use is as follows... � Measure 100cm of water in to a glass beaker � Place the beaker into the grasp of the clamp stand.
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If there are any anomalous results, they will not be included because they will make the average odd. I will need to wear goggles and tie back long hair for safety issues. The Bunsen burner will always be kept on a safety flame so it is visible. Prediction I predict that as the number of the carbons in the alcohol increases, the temperature rise in the water will increase. The bond energies show that the more carbons there are in the alcohol the more energy is given out. This reaction is exothermic so it will lose energy. Methanol Methanol + oxygen --> carbon dioxide + water CH4O + 1.5O2 --> CO2 + 2H2O (1)
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