ocr a f325 revision thread

Honestly, that one I did not understand. There did not seem to be any obvious method, other than the fact that lactic acid is just more well known for being in food.

Maybe because the Pka is very close to the pH lol?

Have you guys done every single paper?

The answer is 0.13 mol per dm cubed.

However, i get 0.013 mol per dm cubed



Could someone please explain why.

question is worth three marks

Mistake in the mark scheme, specimen mark scheme has loads of mistakes in it btw.

ahh thank you, so is 0.013 correct then?

MS also says some weird thing about halving phenol conc. at firs

I think it is saying you could take the 0.2 value from either phenol or its conjugate base.

Sorry, but what do you mean?

It says you have the same concentration of phenoxide as phenol. But a potential marker would not know if you chose the value of 0.2 from the phenol, or deduced it was the value for phenoxide. I am not certain, but I think that is all it means.

ahhh okay

how are you feeling about the exam?

Pretty much doomed.

I'm sure you'll do great hehe

Well I was aiming for an A* until I was incapable for 2 months due to illness... I have literally had to learn the entire module over about 3 days. I only just did all the past papers today (yesterday now hehe). If I was confident I would be sleeping now instead. Also because I have an exam clash I am doing this exam at 9:00am. But don't think I will telling anyone the answers :P

It is impressive to have learnt everything withing 3 days!

I'm sure you will still do very well

Good luck with both of the exams

Thank you, I wish you all the best too.

ahh thank you, so is 0.013 correct then?

MS also says some weird thing about halving phenol conc. at firs

Yep. Good luck everyone, hope this isn't as hard as January, I want to get my B and be done with this.

Yep. Good luck everyone, hope this isn't as hard as January, I want to get my B and be done with this.

Well I was aiming for an A* until I was incapable for 2 months due to illness... I have literally had to learn the entire module over about 3 days. I only just did all the past papers today (yesterday now hehe). If I was confident I would be sleeping now instead. Also because I have an exam clash I am doing this exam at 9:00am. But don't think I will telling anyone the answers :P