Chemical Equation
CaCO3(s) + 2HCL (aq) H20 (l) +CO2 (g)
Preliminary Tests
Prediction
I predict that the more concentrate the acid solution (acid rain) then the quicker and more violently the reaction will take place. I think this because the more concentrated the solution is, then the more acid particles there will be to collide with the limestone particles, the force of these collisions will be increased.
Diagram
List of apparatus
Hydrochloric Acid
Distilled Water
Limestone Pieces
Weighing Scales
Boiling Tube
Measuring cylinder small and large
Tub
Bung and tube
Boss Clamp
Stand
Goggles
Stop clock
Test tube rack
Safety
Firstly whenever handling acids you should always wear goggles. I also made sure that the equipment was set up in a safe area and that it was set up correctly.
Also because there was a lot of water being used in my investigation I kept some paper towels near by to deal with spillages.
How was it a fair test?
To keep it a fair test I did the following things.
- The Volume of acid and water combined would stay the same in all of my tests.
- I tried to use limestone chips that were about the same size. I did this because if they were smaller in one experiment then it would have created a greater surface area for reactions to take place.
- I will also keep the mass of the limestone chips equal in all of my tests.
Table of Dilutions
Method
I have chosen to use two dilutions for my preliminary tests. I chose 4 Acid: 8 Water and 8 acid: 4 Water
Using a measuring cylinder I firstly measured out 12ml of acid and then poured it into a boiling tube. Then I measured out 8ml of water and added this to the acid.
I then weighed out 5g of limestone chips. I then filled the tub half full with water; I also filled a large measuring cylinder with water too and submerged it in the water. I the used the stand and boss clamp to secure the boiling tube near to the tub so that I could feed the tubing from the bung into the submerged cylinder. Once I had made sure this was set up correctly I then mixed thee limestone and acid solution together in the boiling tube and started the timer. I recorded how much gas had been collected every ten seconds until it had stopped reacting.
I then repeated this but using the other solution that I had chosen.
Preliminary results
4cm3 Acid 8cm3 water
8cm3 acid 4cm3 Water
Conclusion
In conclusion I think that the greater the concentration the acid is, the quicker the reaction rate will be between the acid and limestone. I think that this is because of collision theory as I explained in my prediction.
Real Tests
1 12cm3 acid 0cm3 water
2 10cm3 Acid 2cm3 Water
3 8cm3 Acid 4cm3 water
4 6cm3 Acid 6cm3 water
5 4cm3 acid 8cm3 water
6 2cm3 Acid 10cm3 water
Analysis
Conclusion
I conclude that the greater the concentration of acid then the faster the reaction between the acid and the limestone. From my results you can see that the higher the concentration of acid the faster a larger amount of gas was collected.
You can also see this on my graph. They are shown by steeper lines showing that a reaction was quick.
Evaluation
I think that results clearly show that the more concentrated the acid rain then the faster the limestone will erode.
Most of my results look accurate except for one in c. I think this because I may have been a bit late timing it. But I could have made my results more accurate if I had more time. For example if I had of had time I would have liked to of made sure that all of the chips were the same size and that I used the same amount for each test (5 pieces weighting 2g each).
Would also have liked to get exact amounts of gas released, as it was hard to read the cylinder accurately. To do this I would use a gas syringe.
The tests could have been continued by using more dilutions, and also doing it at different temperatures. For example erosion of limestone may happen quicker when it is warmer compared to when it is freezing or cold.
