Wow, the experiment is over, all my work is handed in, and I suppose this is my last post on my SRP. So, I actually did learn stuff about boiling point elevation and i've already discussed the purpose of the experiment and what the results showed. Something I forgot to mention on my blog was that I learnt something else new! It's called the v'ant Hoff factor and it played a really big role in my experiment. It is the dissociation factor. In my experiment there was salt- an electrolyte, sugar- a non- electrolyte and baking soda- which became an electrolyte when added to water. The fact that salt and bicarb soda were electrolytes meant that it was expected that they would have higher v'ant Hoff factor and therefore, the boiling point elevation was expected to be higher for them. I already discussed vapour pressure and how it influenced the outcome but even before going into vapour pressure- the intermolecular forces played a big role.
So, a few weeks ago, I didn't even know what vapour pressure was and now the SRP is done and over.
oh btw, did you get the pun in the title? hahahaha, i thought it was very punny :)
Wednesday, June 16, 2010
SUMMING UP
seeing as this video is taking forever to upload, i might as well finish the rest of this off noww....
SO:
The purpose of this whole experiment was to investigate how the gradual addition of non-volatile solutes affects the boiling point of water. Based on background research, I found that what was supposed to happen was that the addition of non-volatile solutes to boiling water will cause the temperature of the water to rise and boil at higher temperatures because of intermolecular forces, dissociation and vapour pressure. Salt, sugar and sodium bicarbonate were added in 20g intervals to boiling water and the highest temperature reading was recorded at each interval. The results show that each solute raised the boiling point temperature of the water. In the experiment, the independent variable is the amount of solute added to the water. The dependent variable is the temperature of the water. I controlled the variables but because of the subjective nature of determining the boiling temperature at a given time, I came across a few errors where the magnitude of the measured increases deviated from the predictions. However, in total, the experiment supported the common hypothesis that the addition of any non-volatile solute to water increases its boiling point.
The experimental results
These pretty much showed the rise in temperature each time- it all agreed with the hypothesis- the water displacement because of evaporation and the percentage in temperature increases.
So after a very long and tiring experiment, I can conclude confidently, that the addition of various non-volatile chemicals to the boiling point of water will cause the temperature of water to rise and boil at higher temeperatures. The results showed that the addition of salt, sugar or sodium bicarbonate to water increased its boiling point temperature. This is in agreement with the common hypothesis that the addition of any non-volatile solute to water increases its boiling point. However, because of the limited capability of the experimental equipment, the magnitude of the measured increases deviated from the predictions.
Raw results + some observations explained
ok so i made some observations in all 3 experiments that i recorded in each of the raw results that as soon as I added the solute to the boiling water, the temperature would immediately decrease and then begin to rise again. My explanation for this is that when the solute is added to boiling water, it obviously has a much lower temperature than the water originally so before it begins to dissolve and dissociate etc... its low temperature causes the water temperature to quickly drop but as soon as it begins to dissolve, the water starts to rise again.
Another important observation that I made was that in each experiment, I could actually see water vapour rising and condensing around the place- like when i looked over the pot, i could feel water droplets on my face so there was a lot of evaporation.
In the baking soda experiment- I actually observed in each trial- there was a big reaction with the water. There was a lot of fizzing and bubbles and spilling over the edge of the pot- I actually have a video of that but it isnt working in this blogger upload!!! Anyway, I've linked this to the production of carbon dioxide gas.
upppdate
I HAVE BEEN SITTING HERE FOR 2 HOURS TRYING TO UPLOAD A VIDEO BUT ITS NOT WORKING!!!!!!!!!!!!!!!!!!!!!!! SO ILL PUT IN MY RAW RESULTS...
Tuesday, June 15, 2010
Update 2
This is how the experiment was set up on the hot plate. At the front is the digital thermometer connected to the thermocouple and into the solution.
These are the 20g measurements of salt. It was the same for sugar and sodium bicarbonate. 
This is the scale that I used to weigh the water before and after and to measure out the different amount of solutes.
This is how I cooled the experiment down at the end before I weighed the solution.
Update
OK, WOW I HAVE NEARLY FINISHED THE REPORT!!! IM TRYING TO ADD THE INTERMOLECULAR FORCES OR WHATEVER INTO IT AND THEN EDIT AND MAKE SURE ITS ALL GOOD AND FIX UP ANY STUFF AND THATS IT! FINISHED. I'm trying to upload all the photos and videos now but its really slow- but I will wait...for now.
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