Affect of temperature on the rate of reaction

... he acidic solusion. The readings should be double-checked by different individuals at 900 from the thermometer. The results must be clearly recorded on a results table.

4) Add the measured 2.5 cm strips of standard magnesium ribbon (from the same coil/source) to the different concentrations of acid, having scraped both surfaces with wire wool to remove magnesium oxide and expose the pure magnesium. Each test tube should be stirred to allow reactants to fully come into contact for the same period of time with the same force.

5) Observe the temperature rise while reaction takes place. When highest temperature is reached and temperature begins to descend record the peak temperature that too should be read at 900 and by more than one person.

6) Once the experiment is complete. Repeat all the experiments in the same way for accuracy.

7) From the results averages can be worked out and graphs can be plotted to show trends and patterns or to prove the prediction.

Experiment 1 Concentration of Acid(Moles) Initial Temperature(Degrees) Final Temperature(Degrees) Temperature Difference(Degrees) 0.25 15 26 11 0.5 15 59 44 0.75 17 40.5 23.5 1 17 43 26 1.25 17 48 31 1.5 18 51 33 1.75 18 52 34 2 16 51.5 35.5

Experiment 2 (Supplementary) Concentration of Acid(Moles) Initial Temperature(Degrees) Final Temperature(Degrees) Temperature Difference(Degrees) 0.25 23 32 9 0.5 20 38 18 0.75 20 43 23 1 20 49 29 1.25 21 52 31 1.5 20 55 35 1.75 20 56 36 2 20 56.5 36.5

Averages of both experiments Concentration of Acid(Moles) Temperature Difference(Degrees) 0.25 10 0.5 18 0.75 23.25 1 27.5 1.25 31 1.5 34 1.75 35 2 36

Analysis

From the results and graph we can see that an increase in concentration has resulted in an increase in temperature.

Increasing the concentration of the reactants increases the frequency of collisions between the two reactants. If we increase the rate of reaction we increase the temperature rise of the reaction; a faster reaction allows more collisions to take place during the same period of time, which means there is a greater chance of more successful reactions when collisions take place. This results in more successful collisions and therefore more energy is released faster, releasing more heat to the surrounding environment and this is what causes the rise in temperature.

However the temperature increases by smaller quantities as the concentration of acid increases (it seems to be levelling off). Possible reasons for this could be that the hydrogen gases produced a ...