Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread

For why salicylic acid was sparingly soluble what did you guys put?
For the differences between acid and base i put that with the base you can separate by adding by acid, but when you hydrolyse with acid you have to separate using distillation
I also put that ammonia is corrosive instead of saying toxic

I messed up the titration curve too omg! 5 marks. I really want an A* as well. And for the entropy one, I said Ssurr will be a slightly less positive value since temperature has slightly increased. I said Ssys will remain the same and so Stotal will decrease by a small amount. ? I can't even remember

i talked about how the benzene ring was non-polar and that the london forces existing between benzene rings of other salicylic acid molecules would be stronger than the hydrogen bonds that could form with water

half equivalence?

S sur becomes less negative, S system constant and S total becomes more positive I think
But i messed that up and thought T was decreased

So pH=pKa1?

well I thought that was harder than usual. Not really hard but Im pretty sure I was never told we had to learn how to draw a Diprotic neutralisation.....or is that just me be badly prepared?

well I thought that was harder than usual. Not really hard but Im pretty sure I was never told we had to learn how to draw a Diprotic neutralisation.....or is that just me be badly prepared?

That question was hard. Really edexcel. They had the same type of question in the IAL chem exam as well.

Yeah so i said at volume which is half of the volume at first equvalence, pH=pKa1

well I put the two pka's at 12.5cm and 37.5cm, I also did 2 Vertical regions. Finally asymptoting off just below ph 13 for the remaining 50cm of excass naoh that was added.
Was kind of making it up as I was going along on that one!! so excuse me if my answer is pile of crap.
What was the general consensus on the paper then?

well I put the two pka's at 12.5cm and 37.5cm, I also did 2 Vertical regions. Finally asymptoting off just below ph 13 for the remaining 50cm of excass naoh that was added.
Was kind of making it up as I was going along on that one!! so excuse me if my answer is pile of crap.
What was the general consensus on the paper then?

What did people get for the one where you had to use a2 maths?

I said Bacl2 was poisonous when soluble when consumed. I should have just said it was toxic. Dammit.

Why were the equivalence points at 12.5cm and 37.5cm? I think I put 25 and 50cm