Chemistry Coursework

* To make this experiment completely fair I am going to put the exact same mass of marble chip in the conical flask every time I carry out the experiment.

* I am also going to keep the concentrations of the same each time I carry out the experiment

* I will make sure that my readings are accurate by taking them every 10 seconds. I will ensure that the volume of hydrochloric acid stays the same at all times so they will not react too fast or too slow.

* Also I will make sure that there is exactly the same amount of water in the measuring cylinder each time I carry out the experiment, I will do this to ensure that I get the most accurate results possible, I am going to make certain that there is no air bubbles.

* I will keep the surface area of the marble chips the same each time.

Equation

CaCO3+HCl CaCl2+CO2+H2O

calcium carbonate + hydrochloric acid calcium chloride + carbon dioxide + water

Range of Results

I am going to use 3g of marble chip

I am going to use 30cm3 of Hydrochloric acid

I am going to take my readings every 10 seconds

The temperatures I am going to use are 20, 30,40,50 and 60 this is my independent variable.

I will repeat each temperature to check that my results are reliable.

Apparatus

Thermometer

Timer

Bunsen Burner

Step-by-step Method-

* Set the equipment up as shown above

* Fill the measuring cylinder with water and make sure that it is secure on the beehive shelf

* Measure 30cm3 of hydrochloric acid put it in the conical flask

* Heat the acid to the temperature you want it by using a water bath and putting the conical flask with the hydrochloric acid in it an heat it with a Bunsen burner to your desired temperature

* Weigh out 3g of marble chip and put it in the conical flask and put the bung on

* Start the timer

* Take readings from the measuring cylinder to see what volume of CO2 has been produced every 10 seconds

* Stop the timer when all the water has been displaced from the measuring cylinder

Variables

* Mass of marble chips

* Volume of Hydrochloric acid

* The temperature of the Hydrochloric Acid

* Concentration of Hydrochloric acid

* Surface area of marble chips

Prediction

My prediction is that the higher the temperature of the hydrochloric acid the quicker the Carbon Dioxide will be produced. The collision theory backs my prediction up; chemical reactions only occur if particles collide and have enough energy, if they do not have enough energy then they will bounce off each other. As the temperature increases the heat energy transfers to kinetic energy, which causes the particles to move faster, so it is more likely for them to collide. The higher proportion of these collisions will lead to a reaction, because of the temperature a higher percentage of the collisions have energy, so the particles on average moving faster. A reaction is speeded up if the number of collision is increased. This means that the hotter the temperature the more likely the particles are to collide therefore causing a chemical reaction.

Preliminary Work

My preliminary work shows that the higher the temperature of the hydrochloric acid the quicker the CO2 is produced. Here are the results of my preliminary work.

Time

(secs)

Volume of CO2 produced when the Hydrochloric acid is 20

Volume of CO2 produced when the hydrochloric acid is 60

10

3

20

20

5

44

30

7

40

9

50

15

60

20

70

25

80

31

90

35

100

42

110

49

I have used the highest and the lowest temperatures, I have done this to get a rough idea of how the results are going to turn out, I have decided that the quantities I have used are suitable for my main experiment because there is a lot of difference between the two temperatures so they will give us a wide range of results. I am going to do my experiment from 20 to 60 at 10 intervals; I am not going to go any higher than 60 because the reaction will take place too fast to record the result.

Obtaining Evidence

Safety

* Goggles- To ensure that if there is spillages your eyes are protected

* Stand up- You have always got to remain standing while doing the experiment so if an accident occurs then you can get away quickly

* Make sure that the apparatus is not at the edge of the table to prevent any accidents

* We do not use high temperatures because it would be very dangerous to deal with and anything over 100 will evaporate so the experiment would not be fair.

Here are the results to my experiment.

Temperature of Hydrochloric Acid ( )

Time taken for the CO2 to be produced (secs)

Volume of CO2 produced (cm )

1st reading

Volume of CO2 produced (cm )

2nd reading

Average volume of CO2 produced (cm )

20

10

2

3

2.5

20

20

3

5

4

20

30

5

7

6

20

40

8

9

8.5

20

50

13

14

13.5

20

60

18

19

18.5

20

70

24

24

0

20

80

30

31

30.5

20

90

34

35

34.5

20

100

41

40

40.5

20

110

48

49

48.5

Temperature of Hydrochloric Acid ( )

Time taken for the CO2 to be produced (secs)

Volume of CO2 produced (cm )

1st reading

Volume of CO2 produced (cm )

2nd reading

Average volume of CO2 produced (cm )

30

10

5

10

7.5

30

20

16

34

25

30

30

27

39

33

30

40

42

30

50

50

Temperature of Hydrochloric Acid ( )

Time taken for the CO2 to be produced (secs)

Volume of CO2 produced (cm )

1st reading

Volume of CO2 produced (cm )

2nd reading

Average volume of CO2 produced (cm )

40

10

13

15

14

40

20

27

30

28.5

40

30

43

46

44.5

Temperature of Hydrochloric Acid (cm3)

Time taken for the CO2 to be produced (secs)

Amount of CO2 produced (cm )

1st reading

Amount of CO2 produced (cm )

2nd reading

Average amount of CO2 produced (cm )

50

10

13

14

13.5

50

20

32

30

31

50

30

50

48

49

Temperature of Hydrochloric Acid ( )

Time taken for the CO2 to be produced (secs)

Volume of CO2 produced (cm )

1st reading

Volume of CO2 produced (cm )

2nd reading

Average volume of CO2 produced (cm )

60

10

25

23

23

60

20

50

48

48

I think that repeating my experiment is important so that I can double-check my results. I did not change any aspects of my plan.

Analysing Evidence and Drawing Conclusions

From looking at my graph I can see trends they are that as the temperature increases the rate of reaction increases. You can see from my graph that it takes a few seconds to get going this may be because the marble chips might have an outer layer of dirt. On the graph this is shown by the higher the temperature the steeper the gradient therefore the reaction is faster, the collision theory backs up my conclusion; when the temperature gets higher the rate of reaction increases this is because the particles have more kinetic energy so they move around more so they collide more often, the high percentage of collisions will have energy making the rate of reaction faster. This shows that my prediction was correct.

Evaluating Evidence

The prediction that I made was correct. I thought that my experiment had a lot of aspects wrong with, I found that it was not very accurate the reasons being the surface area of the chips are very hard to control. I had to look for approximately the same size chips each time I carried out the experiment so I could maintain just about the same surface area. Also trying to maintain the temperature of the acid was very hard, to prevent this a thermostat could be used, there could also be parallax errors made. The bung is a very big issue because it is very hard to get the bung in the conical flask quick enough so there is gas lost. To prevent this happening could put the conical flask on a balance and measure the weight of the flask as CO2 is produced.

For this experiment I did not get any anomalous results this shows that my results are reliable and shows that I can rely on my results. The results that I obtained are a good set, there is not a lot of difference between the first times I carried out the experiment and the second time I carried out the experiment, this also shows that my results are reliable. If I were to repeat the experiment I would use more reliable equipment like a thermostat to keep the temperature at a constant and I would put the conical flask on a balance so I could see volume CO2 is being produced more accurately.

The change of equipment would make the experiment more accurate; this would make my results even more reliable. My experiment was a fair test. I did not have any difficulties throughout my experiment.

If I were to do my experiment again I think that I would go above 60 to see if the volume of CO2 stays the same as at 60 of the reaction keeps getting faster.