Compare the theoretical masses of CuO to the actual masses obtained in the experiment

7. The CuCo3 will begin to turn black and the particles will begin to bounce around.
8. Keep moving it in and out until the reaction has stopped.
9. Let the test tube cool down until you can pick it up with your hands.
10. Take the mineral wool out to allow all the Co2 to escape so you are just left with CuO.
11. When the test tube is cool enough weigh it on the scales and record the results.
12. Now minus the results with your starting amount.
13. Repeat all these steps but use different amounts of CuCo3 in stages of 0.5g.  So do 1.5g, 2g, 2.5g, 3g, 3.5g,4g, 4.5g,5g.

RESULTS:

Mass of CuCo                Calculations                                mass of CuO

        

1g                                16.97   - 16.64                                0.33g

1.5g                        14.65   – 14.60                        0.50g

2g                                23.94   – 23.28                         0.68g

2.5g                        15.10   – 14.28                        0.82g

3g                                16.40   – 15.40                        1g

3.5g                        16.90   – 15.80                        1.1g

4g                                19.88   – 18.54                        1.34g

4.5g                        27.668 – 26.20                        1.468g

5g                                22.3     -  20.70                        1.6g

My results came out near perfect to what I actually predicted.

FAIR TEST:

You want the experiment to be as fair as possible, here are some major points to do.

1. Dry test tubes.  You can dry them by using a Bunsen burner.
2. Must use mineral wool and not cotton wall because cotton wool will not be able to hold in the carbon dioxide, it is not as compact as the mineral wool is.
3. Must use a strong bunsen flame so that the reaction can work at its optimum heat.
4. If you use too big a mass of CuCo3 the results obtained can be too large and inaccurate.

ANALYSIS:

As you can see the graphs are very similar.  The theoretical mass graph is a perfect line, this shows there is a direct proportion relationship in theory if you double the mass of copper carbonate, the mass of CuO should also double.  The theoretical graph compared to the actual mass graph of the experiment is nearly identical. There is only a few points that are off the line of best fit.  These could be due to a number of reasons: The test tube may have not been dried properly; the powder may have been wet; or the reaction was cut short for some reason.

Here is a comparison between the theoretical mass of CuO and the actual mass obtained in the experiment:

Theoretical Mass of CuO                        Actual Mass of CuO

35. (2.dp)                                        0.33g

0.53        (2.dp)                                        0.50g

0.71        (2.dp)                                        0.68g

0.89        (2.dp)                                        0.82g

1.06        (2.dp)                                        1g

1.24        (2.dp)                                        1.1g

1.42        (2.dp)                                        1.34g

1.59        (2d.p)                                        1.46g

1.77        (3d.p)                                        1.6g

        

As you can see both the masses are very similar.  I am going to calculate the percentage yield of CuO for each mass of copper carbonate.

PERCENTAGE YIELD:

Whenever a reaction takes place, the starting materials i.e. the reactants, produce new substances i.e. the products. The greater the amount of reactants used, the greater the amount of products formed.  Percentage yield is a way of comparing the actual amount of product made which is the actual yield to the amount of product theoretically expected, which is the Predicted Yield.

A 100% yield means that no product has been lost i.e the actual yield is the same as the predicted yield.  A 0% yield means that no product has been made i.e. the actual yield is zero.

Percentage yield is calculated using the formulae:

        

Percentage yield = Actual Yield      x 100%      

    Predicted Yield

1g of CuCo3  =    0.33    x   100%  =  94 %

                             0.35

2g of CuCo3  =    0.68    x   100% = 96%

                              0.71

3g of CuCo3  =    1.00    x   100% = 94%

                              1.06

4g of CuCo3  =     1.34    x  100% = 94%

                               1.42

5g of CuCo3 =     1.60     x  100% = 90%

                              1.77

EVALUATION:        

I think my experiment went quite well.  I was very surprised to see the very close comparison between the theoretical mass of CuO and the actual mass produced.  I think that I could have repeated the experiment two more times so that I can be sure that the results I obtained were correct.  Then I could have taken an average.  This may have given me that extra filter so that the faults in the graph would be corrected and the theoretical mass of CuO would identically match the actual mass produced in the experiment.

I was surprised when I calculated the percentage yield for the mass of CuO I had the results of:

1g        94%

2g        96%

3g        94%

4g        94%

5g        90%

These results are very strange, the actual percentage yield should be around:

1g        50%

2g        80%

3g        85%

4g        60%

5g        40%

The difference in the percentage yield is very large,this could be due to a number of problems.  Problems that may have occurred in weighing or miscalculations.

The experiment overall went well and I found that there is a direct proportional relationship between the theoretical maths of CuO and the actual mass produced in the experiment.