The 4 things that affect the rate of a reaction is the temperature, concentration, surface area and also the catalyst.
I think the higher the concentration of the Hydrochloric acid, the more faster the reaction will be with the Magnesium .The reaction will be faster, if the acid is more concentrated.
The word equation for this reaction is:
Magnesium + Hydrochloric acid Magnesium chloride + Hydrogen gas
The symbol equation for this reaction is:
Mg(s) + 2HCl (l) MgCl2 (aq) + H2 (g)
Prediction:
The higher the concentration of the Hydrochloric acid, the quicker it will take for the Magnesium ribbon to dissolve.
To test my prediction is correct, I will use 4 different types of Hydrochloric acid concentrations, and these are 0.5M, 1.0M, 1.5M and 2.0M.
I will also time how long it takes for the Magnesium ribbon to dissolve, for each of the concentrations.
The quickest reaction will be with 2.0M and the slowest with 0.5M; this is because there are more acid particles reacting in the 2.0M.
Method:
- Measure 10cm of Hydrochloric acid in a measuring cylinder, concentration of hydrochloric acid.
- Pour in the concentration of Hydrochloric acid into a test tube, and add Magnesium ribbon.
- Record the time taken with a stop clock for Magnesium ribbon to dissolve.
Repeat this 3 more times so that we can get an average result for the graph.
- Do the same thing for the other concentrations;
1.0M, 1.5M and 2.0M.
- With all the results we can now work out the average time it took for the Magnesium ribbon to dissolve, for each M.
Fair test:
To make it a fair test, I will keep the size of the Magnesium ribbon (2cm) the same and keep the Hydrochloric acid volume 10cm.
To make it reliable, I will repeat the test 3 times for each concentration and take an average of the time taken for the Magnesium ribbon to dissolve.
Results:
The results I found from the experiment are as follows:
I got the average by adding all the time together and dividing it by the number of times we did the experiment (3)
Conclusion:
My results were fairly accurate.
My results are not very accurate. The thing that isn’t accurate is the relationship on the results table of the molars and that is on the 0.5 section where it says300.49 for the first test and then 360.42 for the second and then after that it says 300.43 when doing the test it hadn’t occurred to me that the results for the 0.5 molar was in-correct, I had later realised that the results were slightly incorrect, I figured this out when I had later realised it
Whilst doing the coursework and as I analysed my steps for the experiment we found out that we may not have actually washed the equipment properly between the tests and after washing there may have water left in the tube that made a result of having slightly in-correct results. I will also check next time if we do a test like this against time then I will make sure that I will not take my eye of the clock just in case the clock had paused for a moment or two.
If I check now to see if have got the graph correct I can check that if I went to 1.25 in between 1.0 and 1.5 and I look at the results for the line of best fit I can see that my results are correct because by reading the graph I can see that the time is less than the 1.0 times and slower than 1.5.
I think I may have got the results wrong because I may have got mixed up with the molars of acid.
My prediction was correct. I found that the higher the concentrations of acid the quicker the time it would take for the magnesium to dissolve.
The higher the concentration of the Hydrochloric acid, the quicker it will take for the Magnesium ribbon to dissolve.
Evaluation:
My results were accurate the second time round. I could make the experiment better by doing it again a few more times, so that I could/may get more accurate results.
If I did the experiment again could do the experiment 5 times instead of three times like in my results.
My method was good and I followed it exactly how I wrote it out and every thing went fine except for the fact that I got mixed up with the result because it was slightly different in the 0.5 molars
