Predictions:
I think that as the two solutions are added together, they will cause the temperature of their solution to rise as the neutralisation takes place. This is because when energy in the form of heat is given out of a reaction it is an exothermic reaction. Exothermic reactions usually need activation energy, the energy to break the bonds in the chemicals and to start the reaction. Once the bonds are broken new stronger bonds are formed. In an exothermic reaction energy in the form of heat is given out to the surrounding when the products are formed. Therefore there is an average rise in temperature. These stronger, bigger bonds are hot, and therefore cause the temperature of the solution to rise.
Observations/Results:
*all volumes in cm cubed.
**all temperatures in degrees centigrade.
As I had predicted, there was an increase in the temperature of the solution. The rise in temperature was steady, and constant, until the volume of Sodium Hydroxide added to the solution got nearer to making the solution neutral. This was because the heat was given out because of the two solutions, the acid and the alkali, reacting with each other to form those bigger bonds in the chemicals. But as the solution came nearer to neutral pH, there was less of the acid to be reacted with for the Sodium Hydroxide, causing there to be not such a sharp rise in temperature as the alkali was added.
Analysis of results:
The results collected from this experiment supported the hypothesis I made, as I have explained above. One thing I was surprised by was the actual rise in temperature at the start of the experiment. I would not have expected it to rise so quickly with so little alkali added to the acid, as it rose 5 degrees with the first 5 cm cubed of alkali added. From these results, I can take from this experiment that in every neutralisation reaction that takes place, heat is given out, meaning it is an exothermic reaction.
Evaluation of experiment:
Overall, the experiment went as planned, but if I were to perform it again, I would definitely make a few changes. The first one I would make would be to have a more reliable way of adding the alkali to the acid in the conical flask, maybe by scrapping the burette and using a measuring cylinder instead. This is because a couple of times I added a little bit more than I was supposed to, meaning the reading may have not been accurate. Another change I would make would be not to put the universal indicator into the conical flask, as this may have prevented the temperature from rising to more than it did. Having said all of this, I am happy with what I did and the way it went.
