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GCSE: Organic Chemistry
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To calculate the amount of energy that each alcohol gives out I have to multiply the amount of water heated (60) by 4.2 and then multiply that answer by the rise in the temperature. Therefore; ENERGY (Joules) = Amount of water heated (ml) x 4.2(ml) x temperature rise (�C) Preliminary experiments To help design my experiment I shall need to do a preliminary experiment. This experiment shall determine how long I burn the alcohols for. Here is a diagram showing how the preliminary experiment will be set up: Equipment needed: * Crucible * Mineral wool * Heat proof mat * Timer Method for Preliminary experiment * Put 3ml of alcohol and a small amount of wool into a crucible.
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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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(The same temperature each time will produce the most accurate results.) -Record the weight of the Spirit Burner containing the alcohol you are testing. -Set the Calorimeter above the Spirit Burner using a Clamp Stand, just high enough for the flame to almost touch the bottom of the Calorimeter. This allows for the maximum amount of water being heated and reduces the amount of air around the flame being heated, as the more air that is heated, the higher the waste of energy, giving inaccurate results. There will also be a draught shield placed around the set-up, to again minimise the heating of air.
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I also used the results of my preliminary work (below) to give me an idea of what might happen. I also used the result from my preliminary work to see how I would set out the results by using the three equations. Preliminary Work: We did the preliminary work as a trial to see what factors should be changed and we were trying to find the factors that would give us accurate results. The preliminary work also gave us the chance to try our equations to figures out energy per mole.
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By using the bond enthalpies this can be done. The estimation for the enthalpy of combustion, using the bond enthalpies are worked out below for each of the alcohols. Methanol CH3OH (l) + 11/2O2 (g) CO2 (g) + 2H2O (l) Energy required in Bond Breaking (KJ mol -1) Energy required in Bond Making (KJ mol -1) 3 x (C-H) 3 x (+413) = 1239 2 x (C=O) 2 x (+740) = 1480 1 x (O-H) 1 x (+464) = 464 4 x (O-H)
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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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Burning Fuels - Fuels are substances that release energy when they react with oxygen. This reaction is known as burning, or combustion. Combustion is an exothermic reaction
CH4(g) + 11/2O2(g) � CO(g) + 2H2O(l) Carbon monoxide is an extremely poisonous gas. If the air/oxygen supply is very limited, carbon (soot) may be formed: e.g. CH4(g) + O2(g) � C(s) + 2H2O(l) Fossil Fuels Fossil fuels were formed from the remains of plants and animals that became buried in sediments millions of years ago. Heat and pressure (in the absence of oxygen) converted these remains into three major types of fossil fuel - coal, oil and natural gas. * * Coal Coal consists mostly of carbon, but also contains a complex mixture of other chemicals.
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I chose to use water as it is safe, easily obtainable, and has a constant, reliable specific heat capacity of 4.2J/�C. The bonds which are made in a exothermic reaction are forces of attraction between the atoms or ions in a substance. These can be of two types: covalent, in which the atoms share electrons. Examples of this are water and carbon dioxide, which has a double covalent bond because it shares two pairs of electrons are shared. The other type of bonds is ionic, where a metal is involved.
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Find out which of five chosen fuels; Ethanol, Propan-1-ol, Butan-1-ol, Hexan-1-ol and Octan-1-ol gives out the most heat energy.
This type of bond occurs when the atoms involved differ greatly in electro negativity. Prediction: I predict that the more energy given out, the higher the number of moles. Method: Equipment: * * Ethanol in fuel burner * Propan-1-ol in fuel burner * Butan-1-ol in fuel burner * Hexan-1-ol in fuel burner * Octan-1-ol in fuel burner * Heat proof mat * 20ml water * Boiling tube * Clamp and stand * Stop clock * Measuring cylinder * Splint/Matches (to light the burner)
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This is an exothermic process, as energy is released and not required. Diagram Aim In this experiment I will aim to see how much hexane and then pentane is required to boil water starting from 20�C (average room temp). I will set up the apparatus as show in the diagram and do the experiment, which I will go through on my plan. In the preliminary experiment, I did not take any results, but observed the experiment closely so as a smooth running takes place in my final experiment, where I will need to collect a good set of results.
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There are several types of cracking including; * Thermal - you heat large hydrocarbons at high temperatures (sometimes high pressures as well) until they break apart. * Steam - high temperature steam (1500 degrees Fahrenheit / 816 degrees Celsius) is used to break ethane, butane and naphtha into ethylene and benzene, which are used to manufacture chemicals. * Visbreaking - residual from the distillation tower is heated (900 degrees Fahrenheit / 482 degrees Celsius, 755 Kelvin), cooled with gas oil and rapidly burned (flashed) in a distillation tower. This process reduces the viscosity of heavy weight oils and produces tar.
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Carbon Monoxide, CO forms when, with rich fuel:air mixtures, there is insufficient oxygen to fully oxidise the carbon (the source being carbon-containing compounds from fuel input). In high temperature products, even with lean mixtures, dissociation ensures that there are quite significant levels of CO. Times during combustion when the oxygen content is often insufficient for complete oxidation are upon starting the engine (when a high air:fuel mixture is necessary), during idling and during acceleration, when the temperature is low or reaction time is short during flame spread in air:fuel mixture (on the lean fuel side).
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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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If only porous rock was present, the oil could get up to the surface, forming shallow lakes. In other places, the porous rock were overlaid by a layer of impervious rock which prevented oil travelling any further and an oil reservoir was created. Natural gas often forms a pocket at the surface of oil reservoirs. What does crude oil contain? Crude oil is a mixture of about 150 different hydrocarbons. Hydrocarbons are compounds that contain only carbon and hydrogen. The majority of hydrocarbons in crude oil are straight chain alkanes, but with the mixture also contains cycloalkanes and arenas.
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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 Heat Energy given out during the Combustion of Alcohols Change as the Carbon Chain of the Alcohols used is increased?
Exothermic is a reaction that gives out energy, normally in the form of heat. It is observed by an increase in temperature. An example of an exothermic reaction is respiration or the burning of fuels. Exothermic reactions have been used for thousands of years-whenever people have burned fuels. When coal is burnt several reactions occur, but the outcome is that carbon atoms from the coal combine with oxygen from the air to form carbon dioxide gas, while hydrogen atoms react with oxygen to produce water vapour. Fossil fuels, such as natural gas and petrol (which is refined from crude oil), contain a high proportion of carbon.
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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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Ionic bonding involves two electrons transferring from one atom to the other leaving an electrostatic force between them. The other is covalent bonding where atoms share electrons to complete their outer shell. An example being methane where four hydrogen atoms each share an electron with a carbon atom. In this investigation, I wish to compare heat produced by the alcohols in terms of: Equal masses. Equal numbers of molecules, i.e. per mole. To calculate the theoretical enthalpy of combustion we need to know the energy requiring in breaking a bond. Methanol (CH3OH) CH3OH + 11/2 O2 = CO2 + 2 H2O Bond Av.
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The narcotic effect of ethanol is well known, and may come about from inhalation of the vapour. Methanol is toxic by inhalation, if swallowed and by skin absorption. If swallowed: wash out the mouth with water and seek medical attention if victim shows drunken symptoms. If vapour inhaled: Remove victim to fresh air to rest. Keep warm. If liquid splashed in eyes: Flood the eye with running tap water for 10 minutes. Seek medical attention. If spilt in lab: Shut off all sources of ignition. Open all windows and apply mineral absorbent to the spill. When heating, eye protection must be worn.
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Do fuel cell systems offer a feasible alternative to combustion engines in minimizing the harmful emissions of transport vehicles?
The essay works like a projection of future driving with focus on the likelihood of fuel cell vehicles being a new mode of transport. Based on a study of what allows the fuel cell system to stand out as an alternative to combustion engines and demonstrate recent ingenuity, some conclusions are made in response to the research question. The assertion is made that while fuel cell systems do make a desirable alternative, their success in bringing down the emissions due to road transport is dependent on the marketing and administration of them.
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This will also apply when replacing the lid after the experiment. I will make sure I keep this experiment fair by carefully controlling the variables. My Preliminary Experiments Before I do my actual experiment I am going to carry out some preliminary experiments to help me decide on how much water I should use in the tin, the time I should allow for each experiment and the height above the flame. I will select the most appropriate and the one that gives the best results and best temperature change.
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Temperature of water before the wick was lit. 21 24 26 20 28 (oC) Temperature of water after the flame was 41 45 45 39 49 blown out (oC) Table 2: Results from the experiment the second time round. FUEL METHANOL ETHANOL PROPAN-1-OL PROPAN-2-OL BUTAN-1-OL Water. (g) 192.8 190.3 194.1 192.7 182.8 Mass of burner and alcohol before the 115 143.7 138.3 143.7 115 experiment. (g) Mass of burner and alcohol after the 113.3 142.6 137.6 142.6 113.6 experiment.
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4.2 is the specific heat capacity of water. This are the predicted results for burning fuels, calculated using bond energies from a book of data. Alcohol Joules/g released Ethanol -17450 Propanol -20850 Buntanol -23070 Pentanol -24700 Hexanol -25930 Heptanol -26890 Octanol -27660 Variables: � Mass of the water 100ml � Type of beaker � Surrounding temperature of around 23�C � The height of the beaker from the wick � Same set of scales Pendiction: I predict that Octanol will release more energy because it has more bonds that the other alcohols, and than Ethanol will release the least due to its few bond properties.
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The aim of this experiment is to compare the amount of energy released when a number of alcohols are burned.
When the burner is closer, less energy is released to raise the temperature of the water, because less heat loss will occur. This is because when the distance is shorter, there is less air in between, so overall, there will be less heat loss to the air during the experiment when the can is closer. Hypothesis Energy changes in reactions are caused by the breaking and making of chemical bonds. Breaking chemical bonds takes in energy and making chemical bonds releases energy.
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'Petroleum.'Crude oil is a mixture of different hydrocarbons and can be broken down into separate fractions by a process called fractional distillation.
The majority of compounds in crude oil are straight alkanes, but the mixture also contains cycloalkanes and arenas. Separation is possible because individual hydrocarbons in the fractions all have different boiling points. As the alkane carbon chain increases in length, the boiling point increase. Fractional distillation takes place in an oil refinery, in a fractionating column. Before the crude oil reaches the fractionating column it is heated until it vaporises. The temperature at the bottom of the column is higher than at the top, this creates a temperature gradient, so different fractions can be drawn off at different levels.
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