OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

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Reply 1840

marioman

Original post by Mathematicus65

100 ums - 55/60
a* - 50/60
a - 46/60
b - 42/60

That's too low for an A I think given how easy the paper was.

Reply 1841

username2097061

Original post by k.russell

Well I think it depends on the specific wording because if it says 'which COMPOUND is formed' then NH3+ is a lost mark bc it's an ion not a compound, however if I remember correctly, it just asked for the products? So if it's products then NH3+ is probs ok..

Fair enough, you have your reasoning and I have mine.

As far as I know, amines reacting with HCL doesn't produce ions, but there you go.

Reply 1842

Iamjos

Original post by MrZebraCookie

But the book says that trans fats behave like saturated fats in the body idek

But you dont know if the alkene groups are cis or trans. thats why I think its the saturated fatty acid

Reply 1843

sydneyl3igh

What was the other organic product in the ethanoic anhydride question?

Reply 1844

ali_t9001

Original post by Irmakozturk

i got quartet for the last one

was the multiplet a sextet?

Reply 1845

RBoss

Original post by Iamjos

How did you work it out?

% yield = mol of A/mol of phenylamine *100

so mol of A = %yield /100 * mol of phenylamine

mol of phenylamine = 3.00/93 = 0.03225...

so moles of A = 0.03225* 0.61 = 0.019677...

So mass = mol*mr = 0.019677...*135 = 2.65645... = 2.66 to 3 sf

Reply 1846

M.Branson98

Original post by sydneyl3igh

What was the other organic product in the ethanoic anhydride question?

Ethanoic acid I think

Reply 1847

WhatALad

They did 3/94=0.032
0.032/0.61=0.0528
0.0528*135=7.1

Reply 1848

maisym00

When naming the type of condensation polymer would polyamide be sufficient or did you need to put nylon

Reply 1849

ali_t9001

Original post by sydneyl3igh

What was the other organic product in the ethanoic anhydride question?

Ethanoic acid

Reply 1850

iaminneedofhelp

Did anybody count 5 carbon environments on the NMR, there was a small little line next to the final peak. Would that signify a straight chain secondary alcohol?

Reply 1851

KB_97

Original post by mil88

Fair enough, you have your reasoning and I have mine.

As far as I know, amines reacting with HCL doesn't produce ions, but there you go.

Can we just let it go. It's just 1 mark. I know for sure I've dropped this mark. I hope I haven't lost more.

Reply 1852

Derek12353

Original post by Derek12353

For me =]
STEP 1: work out moles of starting substance
STEP2: multiply this value by 0.61
STEP 3: multiply that value by mr of A

i got 2.66 though

Reply 1853

lai812matthew

Original post by Derek12353

really? the NMR question from last year would have finished me !

I am quite good and that, on the other hand, I tend to stumble at word questions at topics like triglyceride, degradable stuff, chromatography. There are quite a lot of them this time, and no nmr for me to back up my marks i am really frightened now :frown:

Reply 1854

ali_t9001

Original post by Iamjos

But you dont know if the alkene groups are cis or trans. thats why I think its the saturated fatty acid

Did the question specify they were naturally occurring? The trans isomers don't occur in nature

Reply 1855

mp_x

For the poly(lactic acid) one I put it is biodegradable and breaks down into co2 and h2o as that is the definition of biodegradable in the book, is this right or is it hydrolysed into the monomers?

Reply 1856

lucyjane_x

Original post by Iamjos

I got something similar like 7.14g! How did you guys work it out?

I did that at first and then realised it was wrong. When I worked out the moles I put this as the actual moles instead of theoretical moles so the division was just the wrong way round, but you should get marks for calculating the moles correctly and stuff.