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An investigation into the heat energy released upon burning different fuels

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An investigation into the heat energy released upon burning different fuels AIM: TO SEE IF THERE IS A RELATIONSHIP BETWEEN THE STRUCTURE OF A FUEL AND THE ENERGY IT RELEASES WHEN BURNT. A fuel is a chemical, which releases energy when burnt. The reason it releases energy is because the reaction between the fuel and oxygen is exothermic. This means that more energy is released to the surroundings when the bonds in the products are made than is taken from the surroundings to break the bonds in the fuel and oxygen. In this experiment, the fuel I am using is alcohol. I am using alcohols because they have a wide variety and they give clear results. There is a large range of alcohols I am going to use in my experiment. Here they are: - METHANOL ETHANOL PROPANOL BUTANOL PENTANOL and HEXANOL. Methanol has only one carbon atom. Ethanol has two carbon atoms. Propanol, therefore, has three carbon atoms. The list above works in order of both hydrogen and carbon atoms. The number of atoms increases as you go further down the list. In this case, Hexanol has the most hydrogen and carbon atoms making it the most likely fuel to burn faster (making the experiment quick but efficient) ...read more.


2. I will use a copper beaker in my experiment so as some of the heat energy will not escape from the beaker into the air. Copper is a good conductor of heat and will heat up the water quickly and efficiently but will also allow heat to escape. 3. I will keep the distance between the wick of the burner and the beaker the same too (1cm) for each alcohol. This is because if I used random measurements, the fuel would burn at different rates, making it an unfair test. 4. I will keep the end of the thermometer from touching the bottom of the beaker so as the heat conducted by the copper will not affect the rise in temperature. This is why I will use a clamp to hold the thermometer. 5. Using a plastic cup lid to cover the top of the beaker prevents some energy from being lost to the atmosphere, keeping most of the heat energy in the beaker. 6. I will make sure to measure the temperature before lighting the burner so I know how much the temperature has to rise to. All alcohols will have a temperature rise of 30�c. This is so the temperature will be kept the same and it seems like decent temperature, not too high, not too low. ...read more.


690666.6J converted into KJ = 690.6666KJ/mole PENTANOL - (mass of ) = 0.25g The '88' below is found by adding the mass numbers of pentanol's equation = 60 + 12 + 16= 88. For 1 mole= 2520 x 88 0.25g = 887040J 887040J converted into KJ = 887.04KJ/mole HEXANOL - (mass of ) = 0.26g The '102' below is found by adding the mass numbers of hexanol's equation = 72 + 14+ 16= 102. For 1 mole= 2520 x 102 0.26g = 988615.3J (1dp) 988615.3J converted into KJ = 988.6153KJ/mole Name Mass in (g) Amount of energy KJ/mole METHANOL 0.48 168 KJ/mole ETHANOL 0.41 282.7317 KJ/mole PROPANOL 0.42 360 KJ/mole BUTANOL 0.27 690.6666KJ/mole PENTANOL 0.25 887.04KJ/mole HEXANOL 0.26 988.6153KJ/mole I have noticed from my tabulated results that the alcohols with the even number of carbon atoms have a decimal number of energy per mole. These are also the alcohols that have none of the number '2' in front to balance out its' equation. The amount of net energy given out increases as the number of carbon and hydrogen atoms increases by the structure of each alcohol. For example, Methanol has a net energy of only 168KJ/mole (because it has a small structure) whereas Hexanol has a net energy of 988.6153KJ/mole (because it has a large structure). Therefore, the larger the structure, the more net energy given out. In this case, Hexanol gives out the most energy. ( Katie Bradley ( 10n1 ...read more.

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