ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: blackmagic on May 10, 2014, 10:47:31 am

Title: Aspirin Sac
Post by: blackmagic on May 10, 2014, 10:47:31 am
Hello people,
Got my aspirin sac on Monday, but I don't know what sort of questions to expect for it. We're allowed to take in a set of questions for the sac that includes a couple of general equations, structural formulas and yields. Could someone help a brother out?????? cheers, peace out
Title: Re: Aspirin Sac
Post by: razmataz on May 19, 2014, 03:45:59 pm
Questions such as. How do you test for purity. As well as why is a salt bonded with aspirin. And lastly the reaction pathways and the different ways of synthesising aspirin
Title: Re: Aspirin Sac
Post by: AngelWings on May 22, 2014, 10:49:35 pm
I'd say all of the stuff Razmataz said and yield. Yield often comes up as a calculation.
Title: Re: Aspirin Sac
Post by: melbin123 on June 16, 2014, 11:40:00 pm

Questions such as. How do you test for purity. As well as why is a salt bonded with aspirin. And lastly the reaction pathways and the different ways of synthesising aspirin
So why does a salt bond with aspirin? Thanks a lot
Oh and also what kind of reaction pathways specifically? :)
Title: Re: Aspirin Sac
Post by: nhmn0301 on June 16, 2014, 11:55:21 pm
So why does a salt bond with aspirin? Thanks a lot
Oh and also what kind of reaction pathways specifically? :)
To increase the solubility of aspirin, you add NaOH, this will create COO-Na+ on the aspirin structure. Since this is ion-dipole bond, this is much stronger than the H-bond that aspirin can make to dissolve => increase solubility.
In terms of reaction pathway, they can ask you about why we prefer to use salicyclic acid + ethanoic anhydride to produce aspirin rather than salicyclic acid + ethanoic acid. The former reaction gives you water as an end product, water can dissolve aspirin, which reduce your yield, and drives the reaction backward.