The apparatus that we will be using are:
- Stop Clock – to time our experiment
- Gas Syringe – to measure amount of gas collected
- Clamp – to hold gas syringe
- Calcium carbonate – part of the experiment
- Measuring cylinder – to measure the solutions
- Hydrochloric acid – part of the experiment
- Balance – to weigh the calcium carbonate
- Conical flask – where reaction will take place
First of all I will set up the apparatus as shown in the diagram. I will then weigh one gram of calcium carbonate. I will then measure the solutions of hydrochloric acid and water. The solutions that I will be using are 2M (50ml HCl – 0ml water), 1.8M (45ml HCl – 5ml water), 1.6M (40ml HCl – 10ml water), 1.4M (35ml HCl – 15ml water), 1.2M (30ml HCl – 20ml water), 1M (25ml HCl – 25ml water), and 0.8M (20ml HCl – 30ml water). I will then pour the solution into the conical flask. Then I will add the calcium carbonate, attach the gas syringe to the conical flask and start the stop clock. I will then stop the stop clock after 60 seconds and record the reading on the gas syringe. I will then do the same for the rest of the solutions. I will then repeat the process for the solutions so that I have another set of readings to ensure that my results are accurate and reliable.
I will do many things to ensure that this experiment is a fair test.
First of all and, and most importantly, I will have to get the measurements and the weights of the solutions and the calcium carbonate as exact, and as accurate as possible. I will be using a very sensitive balance to ensure that I can get the best readings possible.
As temperature is a facture that affects the rate of reaction, I will keep the temperature of the solution constant to ensure that I do not get mixed results.
Another important factor of a fair test is to star and stop the clock the as quickly as possible. This meaning that we should start the clock as soon as the calcium carbonate has been put into the solution and the bung on the gas syringe has been placed on the conical flask, and stop the clock as soon as 60 seconds have passed.
I will also ensure that before putting the solution and calcium carbonate into the conical flask, the gas syringe is reading 0 so that our results are accurate.
Results table
Rate of reaction = Amount of gas produced
Time taken
Analysis
From the graph above, you can clearly see that there is a relationship between the concentration of the acid and the rate of reaction. This relationship is that the higher the concentration of the acid, the faster the rate of reaction. This is because the higher the concentration of the hydrochloric acid is, the higher the chance of the bonds in the calcium carbonate breaking because the stronger the hydrochloric acid is the more energy the molecules have so they travel with more force, colliding against the calcium carbonate more frequently per second, which means the bonds will break. If the molecules do not have much energy they will not collide with the calcium carbonate as frequently per second and will just bounce of the bonds harmlessly. This shows that my hypothesis was correct.
Evaluation
In this experiment, we followed the plan correctly, I believe we gained accurate and sufficient enough results to conclude the experiment, and to prove my hypotheses.
My final results were very reliable, due to the precautions I took to make this a fair test, also because the graph clearly shows that all of our results are near or on the line of best fit.
There were two results that were slightly off the line of best fit. However, these results still fitted in with the pattern and relationship. These results were for the 1.2M and 1.4M solutions.
To make this experiment better, I believe that we could have kept the surface area of the calcium carbonate constant. This is because the surface affects the rate of reaction and if we kept the surface area constant, our results would have been more accurate.
To get extra useful evidence in this activity I could use the same apparatus and the same method as this experiment, but instead of seeing how much gas the reaction produces in a certain amount of time, we could see how long it takes for the reaction to produce a certain amount of gas. This would give us extra useful evidence, from which we could come to more conclusions.
Overall, given the apparatus that we were given to carry out the test, I think this experiment turned out to be very successful, and I am very pleased with my results and findings.
