Percent Error & Percent Difference

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By now it is quite clear that this investigation could have given more promising results because the extent of Percent Error does signify and question the reliability of the data collected during this experiment. But, nonetheless, the reasons why these errors came to be are explained in the following.

There was extensive loss of heat in this experiment, and clearly was the major flaw in this investigation. Nearly, 85% of the heat from the lamp failed to come in the vicinity of the bottom of the stand itself. This was a major loophole and led to a reduced temperature rise in the water. If it wasn't for this error, the data collected wouldn't have had such a magnitude of variation with the literature values.

As can be seen from the images, the wooden lid didn't completely cover the calorimeter, there was a gap for the placement of the thermometer. This also contributed towards the loss of heat during this investigation. It cannot be said that there was no loss of water as there were possibilities where evaporation could have taken place; this inevitably reduces the mass of the water, thus questioning the control variable of maintaining a consistent mass of water. It was mentioned in the qualitative observations that the flame was a bluish yellow, thus indicating that there wasn't a sufficient supply of Oxygen. This creates the consequence of Carbon monoxide production instead of solely Carbon dioxide.

This further results in a reduced value for the standard enthalpy of combustion because the reaction has not been completed. There was heat absorbance from the beaker of copper, this heat absorbed by the beaker should have been going towards the change in temperature of the water. This should've been kept into consideration in the calculations as the specific heat capacity of copper. There was a lack of calibration towards this.

Random and Systematic errors exist in experiments and this experiment too has its own set. Random errors can be reduced but those which are systematic are more difficult to control. Needless to say, systematic errors did exist in this investigation. This would further enhance this evaluation. As can be seen from the tables and graph above of literature vs. experimental values in terms of standard enthalpy of combustion, the significant variation can be attributed towards the above factors which contributed towards heat loss, but nonetheless the data collected in this investigation was satisfactory enough to prove my hypothesis.

The standard enthalpy of combustion does increases in a directly proportional manner with the increase in the total number of carbon atoms per molecule, as can be seen in the other graph of the experimental values.

Other Possible Improvements that could be made to this investigation would be:

1. The spilling of alcohol can be something that would be easy to avoid. Ensure, no liquid spills out amid the combustion.
2. Dark hued cardboard can likewise be utilized for averting the loss of heat.
3. Temperature control in the room in which the investigation took place could have been better.
4. In order to have a more equal distribution of heat throughout the water, it must be stirred properly.
5. Further insulation of the calorimeter would have prevented any excessive loss of heat, wool is one example of what could have been used for this purpose.
6. Any advanced thermometer would enhance the exactness of estimation.
7. An increased supply of oxygen in order to reduce the probability of incomplete combustion.
8. Increasing the number of alcohols being tested on would result in more varied data which would further enhance this experiment.

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