way. I will also not change the solute amount by measuring the amount out by using a spatula. I will also not change the solute type by checking before I start that I am putting copper sulphate in the solvent. To avoid any other small errors in the final measurement I will also keep the same beaker and scales by checking that they are the same ones before I begin.
To make sure that I am safe during this experiment I will wear protective goggles throughout, make sure that I have tucked in any lose items of clothing, make sure that I have a heatproof mat, check with my teacher that I have a safe plan and make sure that I am careful with the solvent and the solute. I will also make sure that I clean up after my experiment afterwards.
Method: First I measured out 15ml of water into a beaker and measured its total weight in grams. Then I placed the beaker onto a tripod and took the temperature of the water up to 20 C. I then placed 3 spatulas of copper sulphate into the water and left it for 5 minutes to dissolve. I then filtered the mixture to get rid of any undissolved solute and weighed the resulting solution. This told me how much copper sulphate was needed to saturate the water at this temperature. I then repeated the experiment but I also took the temperature of the water up 10 C every time up to 60 C. I also repeated the whole experiment again to get a more accurate average result for my graph.
Results: Tables:
1st Experiment: Temperature Mass at Mass at Difference
of water ( C) start (g) finish (g) (g)
20 C 63.89g 62.48g - 1.41g
30 C 63.89g 64.70g 0.81g
40 C 63.89g 62.92g - 0.97g
50 C 63.89g 63.96g 0.07g
60 C 63.89g 64.29g 0.40g
2nd Experiment: Temperature Mass at Mass at Difference
of water ( C) start (g) finish (g) (g)
20 C 63.89g 62.78g - 1.11g
30 C 63.89g 64.95g 1.06g
40 C 63.89g 64.03g 0.14g
50 C 63.89g 63.93g 0.04g
60 C 63.89g 64.68g 0.79g
Average: Temperature Mass at Mass at Difference
of water ( C) start (g) finish (g) (g)
20 C 63.89g 62.63g - 1.26g
30 C 63.89g 64.825g 0.935g
40 C 63.89g 63.475g - 0.415g
50 C 63.89g 63.945g 0.055g
60 C 63.89g 64.485g 0.595g
Mean 40 C 63.89g 63.872g - 0.018g
Guillaume Wright 9C2
C/W What effects the solubility of copper 21/5/00
sulphate (page3)
Conclusion: From our experiments that we have carried out we have found out that the solubility of copper sulphate is affected by the temperature of the solvent that it is dissolved in. We have also found that the warmer the solvent that the copper sulphate is dissolved in is, the more copper sulphate is dissolved in the solvent. This was because the warmer the solvent was the more thermal energy it gained and thus giving the solvent particles more energy to move about. This made the solvent particles move further apart from each other allowing more space for the copper sulphate particles to dissolve in which meant more sulphate particles were needed to saturate the solvent at this particular temperature and thus the saturated solution would have gained more weight.
Evaluation: I think that our experiment went quite well although it could have been more reliable. We have not done enough experiments to rightly predict and give the fact that heat does affect the solubility of copper sulphate. In this case our results are not as reliable as they could be. We could improve the reliability of our results by doing the experiments more densely and taking the temperature of the water up 5 C every time and increase the temperature range up to 95 C. We could also have made the results more accurate by doing the experiment more times e.g. 5 times to get a more accurate and reliable average of results.
We had a couple of unusual results in that in 2 of our average results the resultant dissolved copper sulphate was a minus value which cannot be right as you cannot take copper sulphate away from something when you didn’t start with any in the first place. This was because during the experiments we lost a certain amount of water which was either soaked up in the filter paper or had been soaked up in the small amount of undissolved copper sulphate. The other three results were fairly close to the line of best fit on the graph, but still they were slightly unusual due to the above reasons and inaccurate measuring.
To improve our experiment we would need more time to do the various stages of our experiment to make them more accurate and to do them more carefully. We could have got more accurate measuring by using more solute and more solvent to get larger amounts of mass so that there is less room for error. If we had soaked the filter paper thoroughly before hand and also had more time to filter the mixture we could have got more accurate and sensible results because we would have retained all of our solvent that we had before filtration, after filtration. Another way of more accurate results would be to evaporate the resulting solvent after filtration leaving behind the true amount of dissolved copper sulphate to give a more accurate and true weight of copper sulphate. We could also have done more experiments at different temperatures so that we could have obtained more results and giving more results on the line of best fit to make it more accurate.
