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GCSE: Organic Chemistry
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Method I have decided that I will: 1. Weigh the spirit burner with it's lid on first. 2. Measure 200cm3 of water and pour that into the calorimeter. 200cm3 is a good volume of water to start off with. Much less than this and the water would heat up to quickly, causing it to evaporate (which requires energy), thus losing energy. Much more than 200cm3, and the calorimeter would overflow. Therefore 200cm3 is a sensible volume. 3. Clamp the calorimeter 5cm above the spirit burner. 4. Note the initial temperature of the water.
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I will need to keep all lose items off clothing tucked in e.g. my tie tucked in to shirt. The lids on the alcohols must be kept on at all times to prevent evaporation of the alcohol or any spillage's. Apparatus � Beaker � Thermometer � Measuring cylinder � Weight scales � Gauze � Tripod . 6 different alcohols . Wood block . Heat mat . Matches The method that I will use is as follows: � Measure 100ml of water into a beaker. � Record the starting temperature of the water. � Weigh the alcohol � put the chosen alcohol under the beaker allowing the flame to just touch bottom of the beaker.
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The oxygen in the Alcohol is also joined to a hydrogen atom thus also to a carbon atom (C-OH). Names such as 'Propan-1-ol', which end in '-1-ol', refer to the position of the -OH group on the carbon chain. In this experiment my Hypothesis is that the more carbon atoms in an alcohol more the heat of Combustion is produced. The Molar Heat of Combustion produced will vary to the amount of Oxygen present. When organic compounds are burnt they produce CO2 and H2O.
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1 x C-O is 1 x 358 = +358 1 x O-H is 1 x 464 = +464 3 x O=O is 3 x 498 = +1494 TOTAL = +4728 = -6004 Heat of Combustion = +4728-6004 ?H = -1276 kJ mol -1 2.) Propanol H H H 1 H C C C O H + 4.5O=O 3=O=C=O + 4O H H H H H Bonds Broken (ENDOTHERMIC) ?H = + Bonds Formed (EXOTHERMIC) ?H = - 7 x C-H is 7 x 413 = +2891 6 x C-O is 6 x 805 = -4830 2 x C-C is 2
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I will do this by making the main factor initial and final masses of all four of the fuels. I will need this for the final formula. After this, I will heat the water. I will take the initial and final temperature of the water. I am to heat the water until we reach a 20?C rise in temperature. We then stop the experiment when we reach this temperature rise. We also work out the change in mass and the change in temperature in the water.
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The combustion spreads from the ignition source to the adjacent layer of gas mixture; in turn, each point of the burning layer serves as an ignition source for the next adjacent layer, and so on. Combustion terminates when equilibrium is achieved between the total heat energies of the reactants and the total heat energies of the products. Combustion may also emit light energy, mostly in the infrared portion of the spectrum. The light emitted by a flame arises from the presence of particles in electronically excited states and from ions, radicals, and electrons.
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3. Prediction Because Butanol has the most bonds, I believe it must use the most energy. Bond Energy (Kj/mol) C - H 413 O - H 464 C - O 358 O - O 498.3 C - O 805 C - C 347 H - H 436 Using the bond energy values (shown above) I will try to work out how much energy the alcohols will give off. For example: CH3OH is the formula for methanol, and it contains 3 C-H bonds, 1 C-O bond and 1 O-H bond. Using the bond energy values from the above table I can work out how much energy is needed to break the bonds of CH3OH by adding all the values together.
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Results: Height of can from burner: 5cm Mass of burner at start = 204.47g. Mass of burner finish = 203.6g. Mass of fuel burned = 0.87g Start temp = 19oC Finish temp = 23oC, Temp rise = 4oC Following the pilot experiment I made some minor adjustments: Height of can above wick down to 4cm to improve contact with flame and stir the water, because the rise in temperature is too little. Apparatus * Glass Beaker * 100ml Water * Spirit Burner * Clamp Stand * 6 Fuels * Thermometer * Top-pan Balance * Ruler Method 1.
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1316 kJ > Ethanol Word Equation Ethanol + oxygen carbon dioxide + water Molecular Equation C (2) H (5) OH + 3O(2) 2CO(2)+ 3H(2) O Structural Equation H H | | H-C-C-O-H O=O H-O-H | | O=C=O H H + + H-O-H O=O O=C=O H-O-H O=O Bond Breaking Values Number Of Bonds to be Broken Type of Bond Relative amount of energy Needed per bond in kJ Total amount of energy needed in kJ 5 H-C 413 2065 1 C-O 358 358 1 C-C 347 347 1 O-H 464 464 3 O=O 498 1494 Total amount of energy needed to
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The crucible containing the fuel and the mineral wool will then be placed underneath the tripod and gauze. I will then use a ruler to check that the distance between the crucible and the gauze is 14cm. A tin can will be placed on top of the gauze, directly above the crucible, it will be filled with 100 cubic centimetres of water. I will then take the temperature of the water, before lighting the fuel in the crucible. I will wait until the fuel in the crucible has stopped burning and then I will take the temperature of the water again.
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Place the heat proof mat onto the side bench under the clamp claw 3) Weigh the sprit burner and record its weight. 4) Place the heat proof mat under-neither the clamp claw and then place the sprit burner on top of the heat proof mat 5) Get the copper container and place it into the clamp claw and tighten so it is suspended in mid-air. Then move the copper container and clamp claw so that the base of the copper container is 5cm away from the base of the showing wick.
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All equipment should be kept in the centre of the table to prevent spillage. After the experiment, also be careful handling the other equipment which might be hot like the tripod. Fair test: A number of precautions will need to be taken when doing the experiment to make sure everything is fair. * The container will always have to be kept the same, so the depth of the water stays the same. * The volume of water must be kept constant (503) and sensible amount of water must be used, as if to little is used the water could evaporate, and there will also be to big an increase in temperature.
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An endothermic reaction is the opposite of an exothermic reaction, it is one, which takes in energy from the surroundings, usually in the form of heat and is shown by a fall in temperature. Activation Energy or Eact represents the minimum energy needed by reacting particles for the reaction to occur. A catalyst, however, make reactions happen easier and quicker by reducing the initial energy needed, this is shown by the lower curve on the diagram below. The overall energy change for the reaction, Delta H ( H), remains the same though.
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The amount of energy that is theoretically released can be calculated when a fuel burns in sufficient oxygen to produce carbon dioxide and water as they are the only products of the reaction. Some of the energy that is released is kept and recycled to keep the fuel burning. The excess energy is given out in the form of heat. Which is called the heat of combustion. 1 mole of any substance always contains an identical number of particles. When calculating the heat of combustion we use the unit kJ/mole this allows you to compare the energy released by equal numbers of molecules.
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In order to enforce minimal heat loss, I would have to insulate the tin and burner to ensure that a) The water did not loose any heat and b) That all of the heat from the alcohols burner went to the water and that none was lost. Another reason for inaccurate results was incomplete combustion. This meant that the product were carbon and carbon monoxide, which can be further combusted to make carbon dioxide, so making up the heat loss.
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It takes 4.2J/kg, (this is the specific heat capacity of water) to raise 1g of water; therefore to calculate the energy released by each alcohol we have to use the sum: ENERGY RELEASED = mass of water x temperature rise x 4.2J. Heat of reaction Chemical bonds are forces of attraction between the atoms or molecules in a substance. Energy is needed to break these bonds and energy is released when new bonds are made. In a chemical reaction bonds between atoms in the reactant molecules are broken and new bonds are made.
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Ethanol is a colourless liquid with a burning taste and characteristic, agreeable odour. Ethanol is the alcohol in drinks like beer and wine. It is also used in thermometers below -38�C because mercury, which is also often used in thermometers, freezes at this point. Because of it's low freezing point it is used as an anti-freeze in car radiators. Ethanol is normally concentrated by distillation of dilute solutions. Ethanol melts at -114.1� C, boils at 78.5� C, and has a relative density of 0.789 at 20� C. Higher alcohols, those of greater molecular weight than ethanol, have many specific and general uses.
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Carbon monoxide is a poisonous gas. It combines with haemoglobin in the red blood cells and prevents it from carrying oxygen, hence reducing the capacity of the blood to carry oxygen 5.11 Recall that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming nitrogen oxides N2(g) + O2(g) ? 2NO(g) Nitrogen oxide is a major pollutant and greenhouse gas 5.12b Recall that sulphur dioxide and nitrogen oxides are pollutant gases which contribute to acid rain, and describe the problems caused by acid rain.
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These ions have difficulty in leaving the cell membranes. Instead, the ions accumulate and this damages the cell membranes. Damage of the cell membranes would cause bleeding. Even though a few milliliters of blood loss wouldn?t be harmful, excessive blood loss due to excessive use of aspirin could cause harm to the individual. 2.2 Properties of Aspirin They have low boiling points as compared to carboxylic acids even though they are polar molecules. This is due to the absence of intermolecular hydrogen bonding between ester molecules.
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5ml of concentrated 1mole/l of sulphuric acid was added turning the solution reddish brown. The solution was titrated with sodium thiosulphate solution until the solution turned pale yellow (during the addition of sodium thiosulphate solution the flask was shaken well to insure proper mixing of the solution). 2ml of starch solution was added turning the solution blue black and the titration continued until the solution go colourless or blue black colour disappear, the reading from burette were taken and the experiment was repeated until two concordant result or readings were achieved. The standardization of hydrated sodium thiosulphate also give the total amount of iodine present in the solution which is useful in the calculation of further experiment (as the concentration and volume of all the solution(potassium iodate,potassium iodide and sulphuric acid)
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Three secondary macro nutrients: calcium (Ca), sulphur (S), magnesium (Mg). 3. And trace minerals (micro nutrients): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo) and selenium (Se). Without nitrogen, green plants would be weak and smaller than they should be. Phosphorus is vital to the growth and health of plants. It assists in converting the sun's energy and other chemicals (nitrogen)
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oxygen according to the following equations: C4H10+13O2 ï 8CO2 + 10H2O C4H8+6O2ï 4CO2 + 4H2O Both of these reactions are very exothermic in nature. Inducing Fluorine in excess into a container of Butene will precipitate a addition reaction when the double bond between Carbons 1 and 2 is broken and attached to Carbons 1 and Two is Fluorine, creating CH2FCHFCH2CH3 or 1,2-diflurobutane Whereas the induction of a halogen in excess into a container of Butane will
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the number of protons in an atom is equal to the number of electrons. Number of electrons= number of protons The number of protons in an atom is called is atomic number or proton number. Each element has a different atomic number. So if an atom has 8 protons it must be oxygen. Atomic number = number of protons. The mass number is the total number of protons and neutron is the nucleus of the atom. Mass number = number of protons + number of neutrons 12 6C The mass number of Carbon- 12 is 12 and its atomic number is 6.
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