I will investigate how alcohols with increasing number of carbons affect the enthalpy change when an alcohol goes under combustion. It seems also true that inaccuracies in measurement of net energy release increase with the Carbon chain length. More reliable equipment could be used if there was necessity for greater accuracy, such as a balance that measured to more decimal places and a thermometer with more precise reading scales. Also the results would be the same or very similar so carbon atoms were the easier option. This is because this alcohol has the largest amount of bonds and so in the end more bonds will be formed, giving out more energy in the exothermic reaction. Put cold water in a copper container then weigh them and record the water temperature.
Furthermore, all paper and material should be on a separate bench during the combustion process. Teaching notes Get the class to record and share the results. Also produced are the products of the reaction, which are carbon dioxide in the form of gas,water and also carbon or soot which is the black substance that forms on the bottom of the tin can. Measure and record its temperature. Replace the burner under the calorimeter and light the wick. These results are highlighted for reference in Figure 1.
Introduction Aim: To calculate the enthalpy changes during the combustion of a variety of alcohols and to compare the results by calculating equimolar quantities. Weigh alcohol container, record weight for before the experiment. Weigh the burner to see what mass of fuel has been burned. My first graph of the average amount of energy produced from 1g of alcohol showed two anomalous results. This is also because the alcohols with more atoms will be using more oxygen from the air and more carbon dioxide will be produced, which reduces the amount of oxygen in the surrounding air so that the burning cannot continue as fully due to lack of oxygen. The graphs in Appendix B and C can be compared in terms of gradient and anomalies, to show the effects on the results when the experiment is performed or calculated in theoretically perfect conditions. Propan-2-ol is volatile and has a low flash point.
I can see that as the number of carbon atoms increase the energy produced also increases showing that more carbon atoms in an alcohol will produce more joules of energy per gram of alcohol burned. If I were to look at these two values; the energy required to break the bonds of the reactants and the energy released when the bonds of the product are made then I am able to work out the enthalpy change of combustion of the alcohol. These changes would reduce energy loss to the surroundings; to equipment and the air particles so increasing the amount of energy transferred and making the experiment more efficient. Uncontrolled Substance Start mass g End mass g Mass change g Ethanol 291. The correlation differential is only minor, due to the nature of correlation assessing any relationship, which in similar conditions for all fuels will always be present. In relation to my hypotheses, it seems that my prediction of the non-linear relationship was satisfied by all of my results, due to the increasing negativity of enthalpy with chain length.
Ethanol is volatile and has a low flash point. I can then compare this figure with my theoretical correlation to gain a fair representation of inaccuracies when experimenting. You do not need to reweigh the empty calorimeter, but you need to reweigh it with the water in it. This was done by first taking the average mass of the fuel used over the four attempts to create a fairer display accounting for some variations, and then using the molar formula. I will carry out the experiments the same each time so that it remains fair and accurate. I am going to investigate the enthalpy change of combustion for the alcohol homologous series.
This will mean that they won't be able to produce as much heat and they may not burn properly and even produce the dangerous gas carbon monoxide or soot carbon. Remove the lid and light the wick. Firstly the accuracy of the apparatus used for measurement was of critical impact to the experiment, as the below table of apparatus and accuracy demonstrates. Light the burner, stir the water with the thermometer occasionally and observe the rise in temperature. This is a random error. This is also proved by my results as they are negative. Figure 2 Methanol Ethanol Propan-1-ol Butan-1-ol Octan-1-ol Average Mass Change 1.
Three minutes was also too long for each experiment and the temperature change was large, making the water rather hot so, I decided to use two minutes as a suitable time to give me a good temperature change. This matches my initial prediction. Mass change if errors were always —0. The average of these results and my final result is: 428. Question Calculate the change in mass and the change in temperature for methanol, using the results in the table. They are all organic compounds. The water will be heated until the temperature has risen to about 80-90 degrees Celsius.
This energy level diagram helps to show how the heat is released in an exothermic reaction. I will perform the experiments in an uncontrolled environment within the lab firstly, and then I will use draught proofing to see if my attempts to improve heat transfer efficiency are productive and also whether or not I should further my efforts to solve other problems. Different forms of fuel have been emerging from many places. When the fuel is burnt it reacts with the oxygen in the air to form the products water and carbon dioxide. And m1 is the mass of water and m2 is the mass of the copper container. As these alcohols are very similar, the main difference varying factor being an increase in chain length due to an increase in carbon atoms, the choice of alcohols will enable me to compare the change in enthalpy of combustion between them. The larger the alcohol molecule, the more bonds will be broken and formed, and therefore the more heat will be produced, so I think that Methanol will be the alcohol to combust the least, followed by Ethanol, Propanol and Butanol, then finally Pentanol, combusting the most.