Session 7 - Evaporation Investigation

Session 7- Evaporation Investigation

Results:
Table 1: Showing the results obtained during the experiment

Graph 1 : Showing the amount of acetone evaporated in mililitres at different increasing temperatures

• Conclusion

From our results we can conclude that our hypothesis was correct. This is because, as we can see in the table and graph, most of the time, excluding the second column, the one of 25ºC, as the temperature of acetone increases, so will it the evaporation rate.This happens because as the liquid warms and it’s temperature increases, the molecules gain more kinetic energy and will therefore move faster, so they will escape at a faster rate as they gain energy to overcome the IMFs.

• Evaluation:

We used a fairly accurate method to complete our experiment, although it wasn’t perfect and contained some errors as we can see in the table and the graph( when we heated acetone up to 25ºC the amount evaporated should have been smaller than when acetone was heated up to 35ºC), but the results were precise enough for us to see if our hypothesis was correct.The first thing we should mention is that we started trying the experiment with water, although we realised that water had high boiling point(100ºC) so we wouldn’t have time to do it in two lab sessions as it took very long for water to evaporate. We then decided to do it with ethanol, however it still didn’t evaporate fast enough. Finally, we decided doing the experiment with acetone instead than water as its boiling point is lower(56ºC). We also had to make several modifications in the temperature, we had to increase it to make acetone evaporate faster and making sure that the higher temperature didn’t overcome the boiling point. Furthermore, at first, we were doing the experiment using measuring cylinder as containers. However, the liquid didn’t evaporate at all (*1). Finally, we realised that the liquid needed a larger surface area so we used beakers instead. Our results could have slight errors due to the fact that we decided to put three beakers at a time to have more accurate results and an average, but as the beakers were put in the water bath one after the other, they haven’t been exactly the same amount of time in the water bath.Also, despite we tried to maintain the temperature as accurate as possible, that was impossible as it increased and decreased a few degrees constantly. It wasn’t 25 degrees exactly, but 26 or 27. Besides, when we cleaned the beakers, we cooled them down and this could have affected the results too. Finally, when warming up/cooling down the liquid to 15ºC, as we couldn’t do it with the hot water bath we had to put the beaker in a sink with cold water and ice. This could have varied our results slightly and make them less accurate. Moreover, in order to cool down the water bath quicker, we had to remove some hot water with beakers and then add cold water again. We could have avoided all these temperature problems using a more accurate material and having more time to do the experiment.In addition, when the amount of acetone evaporated was smaller than 1 mL we had to use smaller measuring cylinders in order to measure the results more accurately. 

(*1)