Combustion of alcohols coursework

heat of combustion lab

Working out the percentage error of the equipment used. Also I have taken results over a large temperature range. This means than all the values in my results will be greater and as values increase so does their accuracy and therefore I am expecting more reliable results.

enthalpy of combustion method

This graph shows that my results showed a similar pattern to the results in the data book. The enthalpy change of combustion is measured in KJ mol There is a chance that I mis-read the bottle and did another fuel e.

If we study the enthalpy change of combustion from the values in the data book we can indeed see that as the number of carbon atoms in the chain increases the enthalpy change of combustion becomes more negative.

So in summary the longer the hydrocarbon the greater the enthalpy change of combustion due to the low volatility.

Enthalpy of combustion lab report

As the temperature will be measured to a higher amount this will mean that the results will be more accurate as the temperature range is greater. A cork lid is placed on the can to reduce energy loss through the top of the container and holes for a thermometer and a stirrer are made. This will stop any sudden breeze or draught affecting your results. I will now construct a graph comparing the results that I obtained through my experiment and the results obtained from a data book. 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. Although the draft excluder did limit the amount of heat lost to the surrounding area, the heat did manage to find other ways out. This graph shows that my results showed a similar pattern to the results in the data book. This is because the distance between the bonds increases. Also I have taken results over a large temperature range. Extinguish the burner and note the highest temperature reached. If we compare the average values obtained by my experiment to the average values from a data book and work out the error this pattern can be further proven. Put cold water in a copper container then weigh them and record the water temperature.

Secure fibre glass around the container to reduce energy loss and place the container between the triangle of a tripod so it is supported over a spirit burner. I also use the temperature rise of the water.

Energy released by burning alcohols

A cork lid is placed on the can to reduce energy loss through the top of the container and holes for a thermometer and a stirrer are made. So in summary the longer the hydrocarbon the greater the enthalpy change of combustion due to the low volatility. Go on heating until the temperature has risen by about degrees. It takes 4. Another way of making sure that the experiment is carried out fairly would be to have all of the lengths of the wicks the same. I do this by using two constants; the specific heating capacity of water and copper. As you can see these results are a lot more reliable than the previous set of results. This is because the distance between the bonds increases. To do this we must provide the activation energy to start off the reaction. As the temperature will be measured to a higher amount this will mean that the results will be more accurate as the temperature range is greater.

As the temperature will be measured to a higher amount this will mean that the results will be more accurate as the temperature range is greater. I will use replicate one of Methanol. To work out the enthalpy change of combustion for the alcohols, I need to first work out the energy transferred to both the copper container and the water.

From these results we can now conclude that there is a definite relationship between the number of carbon atoms in the chain and the average worked out enthalpy change of combustion.

What affects heat of combustion

Weigh the spirit burner. But I need to take into consideration that heat energy will also be transferred to the tin can as well as the copper container from the flame, so I will include their total mass in my calculations. I will then calculate the change in temperature of the water before and after the experiment. Secure fibre glass around the container to reduce energy loss and place the container between the triangle of a tripod so it is supported over a spirit burner. The enthalpy of combustion becomes more negative as the alcohol molecules become larger. I am now not going to use fibre glass for insulation as it cannot be placed over the sides of the tin can. Write this into the table. Sources used in the analysis. I would also need to reduce the distance between the flame and the bottom of the calorimeter. Put cold water in a copper container then weigh them and record the water temperature.
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