The differences between the Enthalpy Changes of Combustion of the alcohols Hypothesis The differences between the Enthalpy Changes of Combustion of the alcohols when calculated using bond enthalpy values are as follows: Methanol ? Ethanol : 587kJ Ethanol ? Propan-1-ol : 617kJ Propan-1-ol ? Butan-1-ol : 617kJ I shall check to see the differences between the Measured Energy values in the Analysis section of the investigation. Analysis The differences between the average Measured Energy values for one mole of alcohol are as follows: Methanol ? Ethanol : 462kJ Ethanol ? Propan-l ?
Butan-1-ol : 233kJ I would say that the first two were fairly normal, and it is because the measured value for Butan-1-ol was so low, that the difference between that and Propan-1-ol was so low. This means that this hypothesis was not supported by this investigation. Analysis: I shall now show you the reactions that took place, the energy produced by one mole which is calculated using the bond energy values, and the average measured energy that would have been measured if one mole of the alcohol was burned. Methanol: Energy Produced Using Bond Energies: 687 kJ Measured Energy Value: 372 kJ Ethanol:
Energy Produced Using Bond Energies: 1274 kJ Measured Energy Value: 822 kJ Propan-1ol: Energy Produced Using Bond Energies: 1891 kJ Measured Energy Value: 1431 kJ Butan-1-ol: Energy Produced Using Bond Energies: 2508 kJ Measured Energy Value: 1702 kJ Bibliography The other sources that I have used for information on this investigation are: Salter’s Chemical Ideas Book Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.