Science Investigation- Changing Temperatures

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[pic 6]

Graph 1

I did the same experiment again since there was no stopper on the boiling tubes in the last experiment. The heat from the reaction could be lost by radiation and going out of the boiling tubes and so this is not an accurate, reliable experiment.

[pic 7]

My second setup:

STARTING TEMPERATURE OF COPPER SULPHATE SOLUTIONS

1st

2nd

3rd

4th

5th

24 °C

Time/ Pieces*

1

2

3

4

5

1 mins

24.2 °C

25.3 °C

26.6 °C

28 °C

28.3 °C

2 mins

24.6 °C

25.8 °C

27.9 °C

29.2 °C

29.3 °C

3 mins

25 °C

26.5 °C

28.2 °C

30.1 °C

29.7 °C

4 mins

25.5 °C

27 °C

28.5 °C

30.5 °C

30 °C

5 mins

25.8 °C

27.3 °C

28.8 °C

30.6 °C

30.5 °C

[pic 8]

Graph 2

Conclusion:

These experiments were exothermic reactions as they both gave out heat giving us measurable rises in temperature.

My prediction (p.1) for this investigation is that increasing the amount of magnesium ribbon will lead to an increase in the temperature (heat released) as well. According to both of the graphs (p.3 & 4), the greater the amount of magnesium ribbon, the greater the temperature rise. The temperature increased throughout the whole experiment, but the ones with a larger amount of magnesium ribbon had a more rapid increase in temperature than the others. The trend is more clearly shown in graph 2.

By looking at the graphs it can be seen that the increase in mass of magnesium ribbon was

proportional to the increase in temperature showing my prediction to be correct. Thus showing that my results agree with my prediction, as the amount of magnesium ribbon increases the temperature increases.

Evaluation:

I think I carried out fair tests in this investigation. I kept the controlled variable (p.1) the same throughout the whole experiment. The first experiment setup was not so accurate since some heat will be lost through the mouth of the boiling tube and by convection. I should add a stopper onto the mouth of the boiling tube. The setup of the second experiment was much better since the plastic cup and its lid prevents heat loss.

There is an anomaly result in the second experiment. According to graph 2, the temperature of 4 magnesium ribbons and the solution is higher than of 5 magnesium ribbons in 3-5 minutes. A possible explanation of this result is that the 10ml of 0.5M copper sulphate solution may not react with 5 magnesium ribbons fast enough since there was not enough copper molecules to react with magnesium. I could have repeated the experiment several times to obtain more accurate results since there wasn’t enough time. I could also modify the amount of copper sulphate solution.

THE END