I believe that with a wide range of measurements and repeating each result 3 times, I will have sufficient evidence to support a valid and reliable conclusion.
I believe that the method I will be using makes good use of the equipment provided. I am using no unnecessary equipment in this investigation, and the apparatus and procedure will be more than adequate to gain accurate results.
Results
These are my results:
Average Results
These are the average results alone:
Conclusion
I have found that the higher the concentration, the more heat energy is released. This is because in a higher concentration, there will be more of an alkali to be neutralised, and more chemical energy will be changed into heat energy.
Chemical Energy neutralisation HEAT ENERGY
(alkali) (neutral)
Evaluation
I think this experiment was successful, because I have found no results which are clear anomalies. When conducting the experiment, I used heat insulating beakers to hold contain the solution. I believe that the results are very accurate, and this is reflected in the fact that the mean average was a figure close to all three results obtained in each category, all results gained including averages fit the trend of the results I had expected.
The procedure used was of a high standard, and was satisfactory to obtain accurate results. It was a suitable method, because I used the apparatus of the highest calibre available to me. To improve the investigation, I would try and use a digital thermometer, to eliminate the possibility of human error in reading the temperature from the thermometer.
I am unaware of any mistakes in the procedure used or obtaining the evidence, therefore I see no reason as to why the results gained are inaccurate, and I fully support my conclusion, and see no reason as to why it could be in any way inaccurate.
To extend this investigation, I would use different amounts of each chemical, to see if there is a different percentage increase in the temperature change when greater or smaller amounts of a chemical are used. I would expect that the greater the amount of an alkali the greater the percentage increase in temperature, because the more of an alkali present, the more will need to be neutralised, and the more heat energy will be reduced.
Another way of extending this investigation would be to investigate further concentrations such as 120% and 140%. This could be achieved by using 36ml and 42ml of 100% concentrated NaOH. Although using concentrations above 100% is impossible, using such amounts of an alkali would achieve the same effect.
In this investigation, I did not have to use any heat energy to start the reaction. If I were to extend the investigation, I would investigate a reaction started by heat, and measure the energy changes in this reaction, as I would expect this to be different to the reaction I have investigated.
In addition, I would like to investigate the possibility that my graph would level off and have a very small or no gradient at all at either or both of the extreme concentrations. To do this, I could investigate more frequent values at the extreme concentrations. I could investigate measurements such as 85%, 90%, and 95% at high concentrations, and 5%, 10%, and 15%.
The graph with more detailed concentrations may look like any of those below:
However, I would expect all the graphs to be straight lines with no levelling off. I believe the effect I have measured is:
Units of Alkali produce = Units of Heat Energy
I could also investigate the speed of the reaction and the amount of heat produced in time. I would expect most of the heat to be produced at the beginning of the reaction, because the reaction reduces the concentration of the alkali as it progresses.
