OCR Chemistry A 2017 Exam Thread (New A Level)

Thank you!! I was convinced I did it all right, went over it more than 3 times. I imagine either people didn't convert the moles they gave into concentrations first before plugging it into Kc or they forgot to give the answer in moles

Clock reaction

Thank you!! I was convinced I did it all right, went over it more than 3 times. I imagine either people didn't convert the moles they gave into concentrations first before plugging it into Kc or they forgot to give the answer in moles

This has been bugging me i got second but my friend got first so im not sure. I got first half life as 900s but then the second i got 500s. I did it so many times as i didnt think they could ask us second but i may have made a mistake. Whichever one it was should get marks for initial rate and then error carried forward for working out k and units!

You had to square root Ka*[SO2]*[O2] then times by the volume for moles.

What did people put for the first entropy question, where it was barium sulfate formed? I put 2mol aq to 2mol aq and 1mol solid so decrease as solid less disordered

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Oh. Well, I guess I've learnt something new. Would have been nice to learn it in lesson before the exam, but hey-ho.

What was the question on calculating the concentration of Ethanoic acid? I can't remember it at all, did it give the pH?

stfu ill brap u up before u can even remember the buffer equation G

How many marks were for the SO3 question and the question about an alternate way of measuring the rate of reaction ?

I reckon 73-75 for an A some math questions were tricky

Anyone get mol^-1 dm^3 s-1 for the units one?

it actually gave those units in the question as well