Can bromine titration determine the unsaturation in fats and oils?

[NicholasAllen]

Hi,
I am in grade 12 and this will be my last piece (and most important) of chemistry assessment. For this assigment we need to choose a quantitative experiment (ie. determining fluroide content in toothpaste, or a wine analysis etc) and then do introductory research on the background chemistry, perform an experiment and also talk about it's real life implications.

I am desperate to find a QUANTITATIVE experiment (preferably using the data obtained to compare products and comment on their relative effectiveness) which will get me a high mark (meaning that it has a lot of chemistry involved - possibly titrations etc. tonnes of background information, and quite relevant to society today).

So far I have done experiments on alcohols as fuels, water quality and fermentation and have found that since these topics are so broad I have been able to achieve well in them, because there is a lot of chemistry to talk about.

So anyway, please if you have any ideas or suggestions on a really good QUANTITATIVE chemsitry experiment (which I could use to compare products of some kind) that would be great!

Also, I go to a small school and we don't have any fancy equipment like spectrometers or anything, so I could only use standard materials and equipment that could be bought.

Thankyou!

 

[Moogie]

what about the amount of ASA in an aspirin tablet? Really easy titration. There is the 'additional chemistry' of the fact that 2 reactions can occur depending on the temperature:

Firstly, the carboxylic acid group of ASA reacts with NaOH in a‘standard acid base reaction to produce sodium acetylsalicylate and water. ASA also contains an ester linkage and this bond is hydrolysed by NaOH to form sodium salicylate and acetic acid. This reaction represents base-promoted hydrolysis, or saponification, of esters.

The second reaction is really slow and doesn't happen to any extent at room temperature but you can design your experiment to show you appreciate it e.g. perform the titration on ice.

 

[Moogie]

you could also titrate the ascorbic acid in fruit juice

 

[NicholasAllen]

thanks guys they are great ideas, but do you think that I would be able to find a lot of introductory research on them that would help make hypotheses(ie. be able to hypothesise which aspirin product would have the largest ASA quantities or which fruit would have the largest vit c quantities)...? Also would I be able to have extensive discussions, evaluations of them and talk about the significance of my findings in the real world?

Thanks

 

[Moogie]

The aspirin idea isn't ideally adapted to the the type of hypothesis you need. It says on the side of the box how much ASA is in aspirin. All you could do is confirm this by your analysis. Or you could compare 'old' aspirin (if any were available) to 'new' aspirin to determine the extent of ASA hydrolysis. If the extent of hydrolysis is significant you could discuss the shelflife of aspirin.

 

[Moogie]

You could titrate a range of fats and oils with bromine to determine the extent of unsaturation. There is much more to discuss with that i think