Relationship Between the Masses of Copper Carbonate and Copper Oxide

Apparatus

Copper carbonate (105g in total)

10ml test tube

Test tube clamp

Spatula

Weighing Scales

Bunsen burner

Heat mat

Protective goggles

Method

To get the right amount of copper carbonate each time we must place the test tube on the scales, notify the weight, and subtract that when we have the correct amount of copper carbonate. In total we will be conducting 6 experiments, and for each new experiment we will increase the amount of copper carbonate heated by 5g. Each portion of copper carbonate must be weighed correctly for it to be a fair test.

Equation for the reaction:

Copper Carbonate → Copper Oxide + Carbon Dioxide

CuCO3 (s) → CuO(s)  + CO2 (g)

When heating the copper carbonate in the test tube it is essential that it be shaken gently throughout the reaction. This will enable the copper carbonate to be heated evenly. Also any excess gas will be able to escape where necessary. It will be easy to judge when the reaction has taken place as the colour of the substance will have changed from the light green of copper carbonate to the black of copper oxide. It is at this point that we will weigh the copper oxide and notify the result.

Results

The results for the masses of both copper carbonate and copper oxide are below:

 

Analysis of results

From the results in the table and the graph we can see an increase in the mass of copper oxide in relation to the increase in the amount of copper carbonate heated. This complies with my prediction. The graph of the results shows that the mass of copper oxide does correspond to that of the copper carbonate. The correlation between the mass of copper carbonate and the mass of copper oxide is very high (0.99). However, it also shows that when copper carbonate is heated some of its mass is lost in the carbon dioxide. The amount of carbon dioxide produced increases when more copper carbonate is heated. However this increase is not consistent, and can fluctuate slightly. The equation for the relationship* between the mass of copper carbonate and the mass of copper oxide is:

Mass (CuO)=0.891 x mass (CuCO3)-0.967g

The inaccuracy of the results is indicated by the fact that the constant is not zero (-0.967g). If interpreted literally this would mean that when the mass of the copper carbonate was 0g then the mass of the copper oxide would be 0.967g!

Evaluation

Although the results generally agree with the theory that the mass of copper carbonate has a relationship with the mass of copper oxide, but as the graph shows the results are not entirely accurate. There are several different solutions for this:

1. We could have controlled factors in the investigation better (e.g. the shaking of the copper carbonate whilst it is heated, because if this is not done properly it can lead to incorrect results).

2. We could have conducted all six experiments on the same day, as such factors as temperature and humidity can change. Which would alter the outcome of the reaction.

3. We could have conducted more than experiments, which would create more detailed results and the graph’s line of best fit would be more accurate.

 

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