How concentration affects the rate of reaction.

Picture A Picture B

Equipment:

* Trough

* Measuring cylinder x2

* Timer

* Beaker of HCL

* Conical flask containing

* Bong

* Rubber tubing

* Different concentrations of hydrochloric acid

* Calcium carbonate

Method:

We set the apparatus up as shown below and have the timer ready.

After the apparatus has been set up, we will measure out the amount of hydrochloric acid and the amount of calcium carbonate and record it to ensure that the volume remains the same for each test, and only the concentration of the hydrochloric acid changes. When both have been measured out equally we pour the calcium carbonate powder into the conical, shaking it to ensure that it is flat at the bottom to make it a fair test and the same each time. We start the timer as soon as the hydrochloric acid is poured into the beaker and place the bong on top of conical flask quickly to ensure that the carbon dioxide produced from the reaction does not escape. We time each test we do for two minutes to insure that the experiment is both accurate and fair. Once the two minutes are up we remove the tube from under the measuring cylinder to prevent the gas from continuing into the cylinder and we can then record the results of the gas collected in the cylinder. We then repeat this test again changing the concentration of the hydrochloric acid to see what affect this has on the rate of reaction. Each test will have to be repeated twice for the same concentration in order for it to remain a fair test.

Results:

Preliminary:

A preliminary test was conducted to help us to come to a conclusion to which would be the best amount of calcium carbonate to use and also which would be the best amount of acid to use in order to insure that they experiment works better.

CaCo

Acid

Time

Gas

Concentration

5g

30ml

2mins

3ml

0.2m

5g

30ml

2mins

26ml

m

5g

30ml

2mins

6ml

0.6m

0g

40ml

2mins

5ml

m

2.5g

30ml

2mins

76ml

m

2.5g

30ml

2mins

54ml

0.6m

0g

30ml

2mins

41ml

m

The results of my preliminary show made me come to the decision that I would use 5g of calcium carbonate as the results would be easier to use if they were not to high and I would use 30ml of hydrochloric acid as the results that were given were a lot better then the results we received when we changed the acid to 40ml.

Main Experiment table 1:

CaCo

Acid

Time

Gas

Concentration

5g

30ml

2mins

8ml

0.2m

5g

30ml

2mins

2ml

0.4m

5g

30ml

2mins

9ml

0.6m

5g

30ml

2mins

52ml

0.8m

5g

30ml

2mins

67ml

m

Main Experiment table 2:

CaCo

Acid

Time

Gas

Concentration

5g

30ml

2mins

8ml

0.2m

5g

30ml

2mins

23ml

0.4m

5g

30ml

2mins

35ml

0.6m

5g

30ml

2mins

37ml

0.8m

5g

30ml

2mins

75ml

m

I repeated the experiments twice to make it a fair test. I can compare each result to see if they are similar and therefore I can see if the experiments were done correctly.

Results graph shown on next page.

Analysis:

As you can see by the graph that my prediction was correct, there is a increase in the rate of reaction as the concentration of the hydrochloric acid increases. I think this is due to the collision theory, the greater the concentration the more particles therefore the higher the likeliness of collision and the greater the rate of reaction. As you increase the concentration the rate of reaction increases this is definitely proven correct within my results. 0.2 moles have less particles in because the solution is weaker and therefore the collision between the particles were not as great as that of 1 mole concentration and the rate of reaction was not as great. 0.2ml only had 8ml of gas given off where as 1m received over 50ml of gas for both experiments. My results proved my prediction correct and shows that the concentration affects the rate of reaction by the stronger the concentration the greater the reaction. The best concentration used was 1ml the results showed a huge increase between 0.8m and 1m. Also there were no anomalous results they all increased as the concentration increased. This proved my prediction right, the higher the concentration the greater the rate of reaction and the greater the amount of gas given off.

Evaluation:

The results of the experiment were the results that I expected to get. I believe that my prediction was also correct because as the concentration became stronger the carbon dioxide produced was being given off a lot quicker; the rate of reaction was greater. I feel that the method I used was also a good method as reflected in my results although maybe if we had used a gas syringe the results could have been slightly more accurate. In the experiment I feel that the results gathered were fairly reliable they all increased along with the concentration. The only major problem that I faced was that we had to try and put the bong on the top of the conical flask as quickly as possible as the reactions with the higher concentration were very fast and the gas could have been lost very quickly. If I had to change any factors to improve my experiment further and make it more reliable I would use a gas syringe as the readings would be more accurate and also I would use the same equipment for each test as it may ensure the reliability and make it a more accurate test. Overall I am confident that the experiment was a success and the analysis and results are correct.

Hayleigh Cattermole M1