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OCR Chemistry F322~ 4th June 2013~ AS Chemistry

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Question 2 part D is wrong. With the head and acid catalyst, You have put the same molecule twice, Where as it the Alkene function group would be to the left on one of them. ( 1-ethyl-pent-2-ene and 1-ethyl-pent-3-ene).

And as for question 7 part D, It asks for a type, not examples. I could be wrong but i suspect they want you to say Alkanes.

Question 3 part A, The answer should be Alkene and Ester.
As for the rest it looks ok.

It's not my MS. There's about 2/3 mistakes I know.

Reply 4281

tetra-s

For 2)d) I thought both boxes were cycloalkenes as there were two places the C=C bond could be?

Reply 4282

Dingusnin

Original post by TheFootyKing19

It's not my MS. There's about 2/3 mistakes I know.

I know, I was simply pointing out some mistakes to put people at ease, So thye wont start flipping out thinking they have made silly mistakes.

Reply 4283

SuperCat007

I think I may have got 89/100... :s-smilie:

I know for sure that I have dropped about 6 or 7 marks by guessing at questions when my mind went completely blank! At the N2O2 one and also at the RAM one because I haven't done that stuff since 2008! But I put 195.1 (from the periodic table), so I may get a mark for guessing. But I don't think I made too many/any stupid mistakes so fingers crossed for August! I have been at uni and you get your marks so quickly it's a bit of a shock to the system to have to wait more than 2 months for results!

I only need about 78% to average an A overall (82 in F321), but the more marks I can get the better. (thinking about applying to Cambridge! :eek:

)

(edited 10 years ago)

Reply 4284

TheSilentFez

I found the paper very easy. For the first time in my life I finished the paper with 16 minutes to spare and anyone who knows me will know that's surprising considering I'm always really slow at doing papers.
The only question I wasn't happy with was the Biodegradable propellant one. I just did some research and there is no such thing as a biodegradable propellant. Biodegradable means it can be broken down by microorganisms. I don't think this word can apply to any gas, let alone propellants.
Anyway, I wrote HCFCs (forgot HFCs existed), but I have a feeling the answer was butane/isobutane.

Other than that though I can't spot any mistakes I've made so I'd say I've definitely got 95%+
If I get 100% I will be over the moon.

Reply 4285

s7a0

Original post by Saif95

Do you think you would get the mark for just writing incomplete combustion on the flame question?

QUOTE]

yeah incomplete combustion of Carbon produces Carbon Monoxide- soot

Reply 4286

Blashnet

Original post by wndms

Oh no.. I put carboxyl and carbonyl...

Posted from TSR Mobile

I AM SO SILLY...

I put the alkene, then saw the O, and assumed it would be an alcohol because H's aren't shown on skeletal formula, then I remembered that if it's an alcohol it would've been OH! :eek:

Reply 4287

Tahera2013

The biodegradable alternative to CFC's was an unfair question. Because HCF's aren't biodegradable and what other alternative could they have meant?

Reply 4288

Blashnet

Was this the tertiary alcohol? :smile:

Photo on 05-06-2013 at 11.02.jpg101.7KB

Reply 4289

TheSilentFez

[QUOTE="s7a0;42982601"]

Original post by Saif95

yeah incomplete combustion of Carbon produces Carbon Monoxide- soot

Carbon Monoxide is not soot. Carbon particulates and other VOCs form soot.

For the question about the total amount of energy given out when 10 moles of gas were evolved, was the answer 1640kJ or 820kJ?
I couldn't decide whether you multiplied by 10 because it was 164kJ/mol or whether you multiplied by 5 because the ΔH of reaction is defined as the enthalpy change which accompanies a reaction in the molar quantities expressed in the chemical equation.

I eventually settled for 820kJ, but I think that's wrong now so bye-bye 100% :frown:

I think what confused me is that "enthalpy change which accompanies..." does not mean the same as "the energy given off when a reaction takes place in the molar quantities..."

Original post by Tahera2013

The biodegradable alternative to CFC's was an unfair question. Because HCF's aren't biodegradable and what other alternative could they have meant?

I agree it was an unfair question, but HCFs is wrong because HCFs aren't CFC alternatives. I think you meant HFCs of HCFCs.
What they could have meant though is butane/isobutane because they are used as propellants and they don't damage the ozone layer at all (HFCs and HCFCs still do)

(edited 10 years ago)

Reply 4290

Gcayte

Original post by Blashnet

Was this the tertiary alcohol? :smile:

Yes I think so :smile:

Reply 4291

Blashnet

Original post by Gcayte

Yes I think so :smile:

yay

Reply 4292

Ché.

[QUOTE="TheSilentFez;42982779"]

Original post by s7a0

I think what confused me is that "enthalpy change which accompanies..." does not mean the same as "the energy given off when a reaction takes place in the molar quantities..."

It would have been 1640kJ!
:biggrin:

Posted from TSR Mobile

Reply 4293

Blashnet

There was also a question about stereoisomers I think..

It said, why do the structures of these 2 things differ,

I put, 'because each C in the C=C bond have 2 different groups attached

Is this correct? :confused:

Reply 4294

daisyrchds

Original post by Blashnet

was it the ridiculously big compound? i put one compound was e/trans and one compound was a z/cis isomer :smile:

Reply 4295

Lagukage4

[QUOTE="TheSilentFez;42982779"]

Original post by s7a0

I think what confused me is that "enthalpy change which accompanies..." does not mean the same as "the energy given off when a reaction takes place in the molar quantities..."

I agree it was an unfair question, but HCFs is wrong because HCFs aren't CFC alternatives. I think you meant HFCs of HCFCs.
What they could have meant though is butane/isobutane because they are used as propellants and they don't damage the ozone layer at all (HFCs and HCFCs still do)

i also put +820.. but im starting to convince myself thats correct.. :L it asked for the enthalpy change that gives 240dm3 which is 10 moles... the equation states that +164 gives you 2N2O so surely you just multiply that by 5?

Reply 4296

Blashnet

Original post by daisyrchds

was it the ridiculously big compound? i put one compound was e/trans and one compound was a z/cis isomer :smile:

yeah it was, the question before was "define steroisomerism"!

Do you think i'd get the mark for explaining what I did?

Reply 4297

camajin

Original post by 344302

For the products of the heating with potassium dichromate, reacting with carboxylic acid and stuff

Did you guys get an aldehyde for the first top right, and then some ester for the second left
Then bottom right I got something and the last box I put h2o??

Posted from TSR Mobile

top left is a ketone. cos its a secondary alcohol
top right is an ester. becos ur reacting an alcohol with carboxylic acid
bottom two r basically. u get rid of the OH and H and u get a double bond forming. but if u remember the structure u can notice that the double bond can form on either side of the carbon

Reply 4298

JimmyA*

[QUOTE="Lagukage4;42983152"]

Original post by TheSilentFez

I'm the same i also put +820 but i'm really not sure anymore because if it was in KJ mol-1 then it does mean per mole and so it would be 1640. Anyway it's only 1 mark as you will get a mark for working out 10 moles.

Reply 4299

hassanakhtaruk

Original post by Varsh05

Yh same,I went blind and divided by 200 instead of 220,coz I didn't read it properly!
We should be able to pick up atleast 1 mark as method marks,seeing as it was only 2 marks!