Year 12s: what will be the first way you research your future options? >>

OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016)

Scroll to see replies

Reply 300

Clintbarton

Original post by 87Mack

nah it was 6H20

I got 6 too. :smile:

Posted from TSR Mobile

Reply 301

ChelK321

Lol had to wait 20 minutes for invigilators to find data sheets

Reply 302

87Mack

Original post by therealbatman365

I got Br2 to make a dibromo haloalkane and then NaOH(aq) to make the diol???

yeahhh boiii i got the same

Ohh lorraine

Original post by Harryg123456

3.3 i got

Also got that

Reply 305

Barklimus

Original post by 2kk2

for the last question were you meant to add Hbr to the alkene so you get a haloalkane which formed the secondary alcohol - what were the regeants and how many marks would you lsoe if you missed out the regeants

Pretty that the reagent for turning the the alkene into the blank product (C4H8Br2) was Br2. Then, to turn that into a diol, you could use NaOH.

Reply 306

87Mack

Original post by Harryg123456

3.3 i got

yes mate

Reply 307

Jitesh

Original post by Clintbarton

It would be halogenation - just Br2 because you can't create -OH from the the H-C formed in nucleophilic addition. The reagents were Br2 and H2O as steam for the second part?

Posted from TSR Mobile

H2O I believe is a weak nucleophile so normally reagents like NaOH are used BUT I don't think you'll lose a mark

Reply 308

h3rmit

Original post by SGHD26716

I used 100 as they mixed the two solutions together

I did this too

Original post by A Sajid

100% sure it was CrCl3.8H20

If you assume the salt was only CrCl3 (no hydrogen or oxygen) then you should get 6H2O, if you've done the empirical formula correctly

Reply 309

RadonGhost

What did people get when it asked for the equilibrium concentration of SO3 in the question asking about yield, I got something like square root of 30 after rearranging the equation and simplified, but I'm pretty sure that's wrong?

Reply 310

87Mack

did anybody get 0.768 for conc of so3?

Reply 311

therealbatman365

What did y'all put for q15 about the non-polar e/z isomers on MCQ?

Reply 312

tamoni4

What was the % error? My answer was something like 1.7%. And I've said that to decrease the error you have to add a bigger mass of hydrated salt so that more water would be lost which will decrease the (error / mass) fraction.

Reply 313

alexisluvbiology

Original post by ukgjyhtrhv

best chemistry exam ive hever done 😃😃 absolutely buzzing but i think grade boundaries will be high around 90%

oi are you serious i flopped that so bad

Reply 314

Clintbarton

Original post by Jitesh

H2O I believe is a weak nucleophile so normally reagents like NaOH are used BUT I don't think you'll lose a mark

Ah yes but I seem to recall them saying something about the fastest route of synthesis? Oh well.

Reply 315

jn998

Original post by A Sajid

No. For that question they gave conc and vol. So you can work out the moles from that. And then using the moles, you can work out mass by doing moles x mr. That would given you the mass in g which is what you need to do q=mct