I am going to investigate the rate of reaction. The reaction I will be using is: Calcium Carbonate + Hydrochloric acid —- Calcium Chloride + water + carbon dioxide. CaCO3 + 2HCl —- CaCl +H2O + CO2 Measurements and Variables: The variables I have chosen to change is strength of the hydrochloric acid which will be 1 mole, 0. 7 mole, 0. 5 mole, 0. 3 mole and 0. 1 mole some variable I will not be using are temperature, mass, density. The measurements I will be using are time (s) and volume in (cm3). Fair Test: To make sure this a fair test I will get exact amounts of the Hydrochloric acid and Calcium Carbonate.
I will also make sure that the Gas syringe is at zero when I start the experiment. I will also try and start the stopwatch as soon as I add the Hydrochloric acid. Safety: To make sure this will be a safe experiment I will make sure I wear goggles at all time. I will wash my hand immediately after the experiment is over, and will make sure I am attentive when handling acid. Prediction: I predict that the stronger the concentration of hydrochloric acid the more carbon dioxide is given off. I think this because there will be more particles in a certain area (15cm3) so there will be more collisions.
I also think that there will be a quantitative relationship that if you double the concentration the rate will double. I think this because of the collision theory. I will be using strategy 3 because the gas syringe gives accurate readings, it’s quick and easy to set up and there is enough for everyone to use them. I am not using strategy 1 because the measuring cylinder isn’t very accurate and has to be perfectly vertical. I am not using Strategy 2 because there are not enough electric scales. Equipment Calcium carbonate Hydrochloric acid Flask Rubber plug tube Gas syringe Stand Clamp.
Stopwatch Trial experiment: I have done a trial experiment to see whether the strategy I am using is the suitable for my investigation. I did this trial with 1 mole 0. 5 mole and 0. 1 mole and timed it over a period of 20 seconds, I recorded these results. 5 seconds10 seconds15 seconds20 seconds 1mole89cm393cm396cm397cm3 0. 5 mole56cm358cm359cm359. 5cm3 0. 1 mole2cm32cm32. 5cm33cm3 As you can see there is a good pattern as the stronger the acid the more carbon dioxide is given off. After these trial runs I have decided to carry on with the investigation with the same variable. Analysis.
I have found out that the more concentrated the solution is the more carbon dioxide is given off. This is because as I stated in my plan that if there is a more concentrated solution there will be more particles in a certain area (15cm3) so inevitably there will be more collisions which is backed up by the collision theory. The Collision Theory is based on the idea that for a chemical reaction to take place, it is necessary for the reacting particles to collide with each other with enough energy to break or form new bonds between the other particles, which is called a successful collision.
If when they collide and they do not have enough energy to break or form new bonds then they will simple bounce of each other, causing an unsuccessful collision. The ranges for my concentrations were from 0. 1 moles to 1 mole with 0. 3,0. 5 and 0. 7 moles in the middle. I repeated the test 3 times for each strength and got 3 similar sets of results. My graphs show me that my prediction was correct as I said that the higher the concentration, the higher the rate of reaction, and that there will be a quantitative relationship that if you double the concentration the rate will double.
My quantitative reaction showed that when you doubled the concentration, the rate doubled, this is because there are twice as many particles in the same volume 15cm3 so there are twice as many collisions so the rate increases by double. I think my results matched very well with my prediction. Evaluation I think that the results I collect were reliable and accurate as I repeated the test 3 times for each concentration and got similar results.
I followed my safety precautions by wearing goggles at all times, washing my hands after the experiment and I was very cautious when handling acid. I got one anomalous result which is pointed out on my graph showing rate of reactions, I think this is due to one of the three tests being to different on my 0. 3 mole tests. I think that the test was fair to a certain extent but their was a few problems such as not being able to put the rubber plug quick enough before the carbon dioxide was released and also that the gas syringe got stuck a couple of times.
Additional evidence to support my conclusion could have included more justifiable scientific knowledge that fitted my evidence. To extend my investigation further I could use the other to methods and see if I get a similar result, which will show me if this investigation was a success or not. If I were to repeat this experiment again I would try and find a more efficient way of mixing the Hydrochloric acid with the calcium carbonate without losing any carbon dioxide.