This is simply because the particles carry more energy and move faster and get to the surface with more energy to break the bonds to change the state from a liquid to a gas.
As the temperature increases, the substance, in this case Acetone gets warmer, the faster the particles within the liquid will move around, in other words, they gain more kinetic energy. These particles now have the chance to move around the surface more often.
The two theories that affect temperature and the rate of reaction are the kinetic theory and the collision theory. The kinetic theory clearly states that the positioning and movement of particles in a substance increases if the temperature increases. Therefore, increasing the temperature increases the energy between the particles and makes them move around a lot more and collide more often with each particle colliding with enough energy to get it past the energy barrier. If this is done successfully, then the collisions should have no problem passing the requirement stated in the collision theory that are: To react particles must collide with enough energy to break existing bonds.
The likelihood of a reaction occurring is increased so in a final research conclusion, increasing the temperature increases the rate
of evaporation speed.
Apparatus List:
Beaker, Measuring Cylinder, Thermometer, Watch Glass, Stop-clock, Bunsen Burner, Water, Acetone, Pipette, Tripod, Safety Mat
Measurements you plan to make and measuring apparatus you will use:
The main measurements that I will take are
- The temperature- using a thermometer (ºC)
- Volume of Acetone- Using a pipette (cm³)
- Volume of Water – Using a measuring Cylinder (ml)
- The Time – Using a stop-clock (s)
Diagram of how I will set my apparatus up
Method
I will set up the experiment as shown in the diagram above. First of all, I will do my experiment at room temperature. I will put the watch glass over a beaker of 250ml of water at room temperature, without any heating. I will put the Acetone on the watch glass using the pipette. I will ensure that I have the correct amount of Acetone on the watch glass. I will time how long it takes for 0.5cm³ of acetone to completely evaporate. I will repeat each experiment three times to get a god set of results to draw conclusions from. I will repeat these steps for the other four temperatures.
Throughout this experiment, I made sure that safety was one of my top priorities. I wore goggles at all times to protect my eyes; I used safety mats. These told me the dangerous capabilities of chemicals that were to be using and what safety measures were needed when using these chemicals. I used a heatproof mat and tripod when using the Bunsen burner and took extreme caution when turning it on and off. I took the same extreme caution when I repeated the results, which I will talk about later on.
2. Obtaining Evidence
3. Analysing Evidence and drawing Conclusions
My results clearly state that as the temperature increase, the rate of reaction goes lower. I have drawn a CURVE OF BEST FIT in between all of my points. This means that the temperature and the time are not in any way proportional.
From my results, I have come to the conclusion that if the temperature of a solution is raised, so is the time for the reaction to occur. The Acetone disappeared more quickly at higher temperature.
At the lower temperatures, the time for the cross to disappear was less because the particles did not have as much energy as they did at the higher temperatures. At these temperatures the particles are colliding with much more energy and thus increasing the rate at which the Acetone evaporates
I have also concluded from my results that the acetone evaporates faster as the temperature gets higher. This is because the particles have more energy at higher temperatures. This leads up to the fact that if they have more energy then the faster they move around and so there is more chance that they will get to the surface by breaking their bonds and transforming into a gas. If I extrapolated my results then I would find that the results would not go down to zero but frighteningly close. This is because, the Acetone, while it is on the watch glass, is only one molecular layer thick, as there is only a minute amount of Acetone, this means that the Acetone is spread out more freely. There would be a point where the particles cannot all escape their bonds
4. Evaluating Evidence
I believe that I did get a suitable range of results for this experiment. I recorded results from temperatures that ranged from 21ºC to 61ºC and I think that this is a very good range to see how temperature affects the rate of reaction. However, I feel that this also reduces the chance of knowing if anything changes if the temperature reaches a certain point. Perhaps doing the temperature even higher would enhance my results but this is also quite dangerous so I cannot really say that I could have improved the range of my results.
I have found some anamolies within my results that have affected the overall conclusion. One of my results, the experiment at 41ºC, does not seem to fit the pattern, as it should. This is probably due to the fact that on the day that I conducted this investigation, there was a mild wind blowing and one of the windows was left open and a breeze from the window could have caused the Acetone to evaporate more quickly than expected. If I was to do this experiment again I would take great care in ensuring the environmental distractions are taken care of i.e. doors and windows closed.
Some other areas in the experiment that I feel I could have improved on were factors like controlling the stopwatch and measuring the amount of Acetone and Water. There is lots of room for human error here. However the inaccuracies due to them were negligible because I paid close attention to these during the experiment.
Overall, this investigation has been a successful one. I feel my results and analysis have been as accurate and reliable as they could have been under the time allocated. However I feel with extra time, I could have repeated the experiment and made it even more accurate. I could do this by, instead of repeating the experiment every 10ºC, I could repeat the experiment more often e.g. every 5ºC
