Hypothesis: If my prediction is to be proven correct, then the time taken to react to the longest strip of Magnesium would take the longest and the short strip would take the least amount of time. We should also see from repeated attempts at this experiment, that the averages would also increase depending on the length of the Magnesium ribbon.
Sketch Graph:
Control Variables: I have chosen not change the volume of hydrochloric acid, and the width of acid will alter the amount and effectiveness of the acid, which will make the rate of reaction speed up and cause an unfair experiment. I have also kept the magnesium strip the same ribbon, as if the width if the magnesium strip is changed, the surface area would become larger and more molecules would be able to collide at one time, which would mean that the rate of reaction would be faster.
Preliminary Work: I have carried out primary experiments to see what I can improve and change. From this research, I have decided not to measure the weight of magnesium rather measure the length, it will give more accurate results. Moreover, I have used Hydrochloric acid of higher concentration, as the more dilute acids were not effective in reacting within the time range allocated for the experiment.
I’ll perform the investigation twice, and include the preliminary results with the main investigation to get a more accurate comparison. The test will take no longer than an hour.
Equipment:
- Hydrochloric acid
- Test tube rack
- Goggles
- Measuring cylinder
- Test tubes
- Stopwatches
- Magnesium strip
Safety Procedure: Place test tubes in rack properly, secure goggles on and tie long hair back. . Keep Hydrochloric acid at a safe distance away and on a safety mat.
Method:
1 - Place 4 test tubes in rack
2- Measure length of magnesium ribbon and cut into four pieces of 2cm, 3cm, 4cm and 5cm
3 - Place one into each test tube
4 - Measure 10ml of Hydrochloric acid in a measuring cylinder
5- Pour the acid into one test tube and start one stopwatch in synchronisation
6 – Repeat this action with other 3 test tubes
7- Stop the stopwatch and record down the timing when it stops fizzing
Results Chart:
Data Analysing: From the results, it seems that the data is consistent yet there are a few fluctuations on the attempts on 5 cm strip. From the chart we can see that the 2nd attempt is much lower the other two tries and even lower than the 3rd attempt of the 4cm strip. Also the 3rd attempt of the same length took to long, and had to be stopped. This is strange, as the previous attempts were able to finish within the time limits whereas this on did not.
Overall, it seems that the pattern in which I had first predicted, in that the larger the magnesium strip, the longer the rate of reaction. This must have been that because of the imbalance between the two types of molecules, the collisions of particles were much slower. Also, the amount of energy in which the particle contains determines the amount of collision the particles the particle can take, as with every collision, energy is lost. If all energy is lost, the particle becomes redundant and in turn meaning the rate of reaction is substantially slower. So with all these factors taking place during the reaction as time goes by, the likeliness of the larger magnesium ribbon taking a long time to react is higher.
Evaluation: I think that length of the magnesium strip may have been too large for the hydrochloric acid, as it took a lot of time even for the 2cm length strip. I think that if the lowest length was to be 0.5cm and the highest was 3cm, it would decrease the amount of time taken to perform the experiment and would give me the opportunity for more tests to be taken and more data to be retrieved.
However, the tests that were performed were a fair test as the method used was very simple, so error wasn’t a large factor. This meant that the solution could react without being tampered with. Although, on performing the second attempt for the 5cm strip, the tube was accidentally split by passers – by, so we had to stop the time and record the time thus far. This could be the cause for the anomalies within the results and if I were to do it again, I would expect the results to be greatly different.
Due to the amount of stopwatches used in the experiment, we were able to get the exact time for each test tube, which was easier for recording than just using one, which I did during the preliminary experiment.
Conclusion: In conclusion, I found out that my prediction was right and that the longer strip took a comparatively longer reaction time than the short two centimetre strip. This can be seen from the evidence gathered, which I believed to be accurate and would appear again if this experiment were to be performed once more.
