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COMPARING THE ENTHALPY CHANGES OF COMBUSTION OF DIFFERENT ALCOHOLS Analysis Results Table Alcohol Initial Temperature (c) Final Temperature (c) Initial Mass (g) Final Mass (g) Methanol 20 35 188.36 186.40 Ethanol 20 35 233.92 232.31 Propan-1-ol 20 35 244.67 243.24 Butan-1-ol 20 35 213.54 212.29 Pentan-1-ol 20 35 195.44 194.46 Hexonal 20 35 217.38 216.66 Alcohol Mass Loss (g) Relative Formula Mass Number of Carbon Atoms Methanol 1.96 32 1 Ethanol 1.61 46 2 Propan-1-ol 1.43 60 3 Butan-1-ol 1.25 74 4 Pentan-1-ol 0.98 88 5 Hexonal 0.72 102 6 Calculations The first step I need to take in calculating the amount of heat absorbed by the water in each experiment is to find out how much energy is transferred to the water to raise its temperature. This can be calculated using the formula: Mass of water (x) Rise in temp (x) Specific heat capacity Energy transferred to water = 200 x 15 x 4.2 = 12600 J I now need to calculate the number of moles in each alcohol so that I can find out the enthalpy change of combustion for the alcohols using this formula: Enthalpy = Energy transferred to water (/) Moles of fuel burnt To do this I will use the formula: Number of moles = Mass Burnt (/) Relative molecular mass Example of Complete Alcohol Calculation Eg. Methanol Enthalpy Change of Combustion =...

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