OCR F324-June 2013 Chemistry

Original post by D4rth

You don't need to know how any of those processes work. In a past paper they stated its a difficult concept and you should just be able to name different ways.

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Oh ok...so we just need to know that to produce a single optical isomer we can use chiral pool synthesis, biological enzymes from nature because nature is good at making single isomer molecules.

Reply 1303

Original post by Gulzar

Oh ok...so we just need to know that to produce a single optical isomer we can use chiral pool synthesis, biological enzymes from nature because nature is good at making single isomer molecules.

Or transition element complexes. :smile:

Hey guys this is my first time doing F324. We do F325 first in A2 Chemistry at my school. I'm doing Chemical Engineering at Uni as I love Chemistry and Maths (love Maths and Further Maths).

I'm looking to get at least 85/90 UMS in this exam for my A* in Chemistry. It's tough but 2 years ago my brother easily got 90/90 so I'm hoping I can do the same. So far I've found the topics really short and easy. Made notes on most of the stuff in the book (that I felt I needed to write down) and done all the questions (spread, practice and exam), the exam quest booklets and 3 papers. First was a mock at school. I got 49/60 where 51 was an A. This was about a month ago though. January 2013. I made so many little mistakes mainly not drawing repeat unit polymers. Anyway now I'm doing papers and hitting the A* boundaries easily but lose out on the 85/90 UMS by 1 or 2 marks due to silly errors. It's literally because I stop thinking and make a really stupid mistake. Like not balancing an equation properly or reading the question. I guess it doesn't help I've been studying in an open environment (music, girlfriend etc) so after today I'm gonna go H.A.M and sit in my room on my own as I did before.

I wanna save some more papers until closer to the exam. So I'm doing the practice and examination style questions from the book again. Making notes on one or two things I forget/never understood.

Got S3 next Thursday. I took it as an extra module. Got 89 - S1 and 94 - S2 so it'll help me in general if I can swap it out for a weaker module. Also Statistics is a very fun and informative subject for me. All the new and efficient methods it teaches me about sampling and data. (It's 90% hypothesis testing).

C4 and F324 the week after. Then the week after that is FP3 which I need a C in to get my A* in Further Maths (without my S3 swapping in to help) and I'm done!

Hope everyone's revision is going well and you all reach your potentials. :smile:

June 2010 F324 was a bitch of a paper. The last question with the Hydroxyamines was awful for me. :frown:

Anyone wanna revise? Ask me some questions. Thanks! :biggrin:

Tldr; Stop every minute in every question and THINK. I feel this is the way to do well in F324. As long as you have the deep understanding and can think to identify the problems you can find the solution!

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(edited 10 years ago)

Reply 1304

master y

12

Original post by Mus1995

Or n from TSR Mobile

how do u know the ums for the ptactice p/?

Reply 1305

Gulzar

Original post by Mus1995

Or transition element complexes. :smile:

Hey guys this is my first time doing F324. We do F325 first in A2 Chemistry at my school. I'm doing Chemical Engineering at Uni as I love Chemistry and Maths (love Maths and Further Maths).

I'm looking to get at least 85/90 UMS in this exam for my A* in Chemistry. It's tough but 2 years ago my brother easily got 90/90 so I'm hoping I can do the same. So far I've found the topics really short and easy. Made notes on most of the stuff in the book (that I felt I needed to write down) and done all the questions (spread, practice and exam), the exam quest booklets and 3 papers. First was a mock at school. I got 49/60 where 51 was an A. This was about a month ago though. January 2013. I made so many little mistakes mainly not drawing repeat unit polymers. Anyway now I'm doing papers and hitting the A* boundaries easily but lose out on the 85/90 UMS by 1 or 2 marks due to silly errors. It's literally because I stop thinking and make a really stupid mistake. Like not balancing an equation properly or reading the question. I guess it doesn't help I've been studying in an open environment (music, girlfriend etc) so after today I'm gonna go H.A.M and sit in my room on my own as I did before.

I wanna save some more papers until closer to the exam. So I'm doing the practice and examination style questions from the book again. Making notes on one or two things I forget/never understood.

Got S3 next Thursday. I took it as an extra module. Got 89 - S1 and 94 - S2 so it'll help me in general if I can swap it out for a weaker module. Also Statistics is a very fun and informative subject for me. All the new and efficient methods it teaches me about sampling and data. (It's 90% hypothesis testing).

C4 and F324 the week after. Then the week after that is FP3 which I need a C in to get my A* in Further Maths (without my S3 swapping in to help) and I'm done!

Hope everyone's revision is going well and you all reach your potentials. :smile:

June 2010 F324 was a bitch of a paper. The last question with the Hydroxyamines was awful for me. :frown:

Anyone wanna revise? Ask me some questions. Thanks! :biggrin:

Tldr; Stop every minute in every question and THINK. I feel this is the way to do well in F324. As long as you have the deep understanding and can think to identify the problems you can find the solution!

Posted from TSR Mobile

Wow you're an engineering student still doing A levels? How do you get such high scores lol...probably work really hard every day :wink:

I'm alright with f324 but it's the same problem with me where I make costly and silly mistakes when not reading the question properly or ruining the balanced equation. Do you have any tips on the mass spec questions like what to look for other than the M+ peak for the Mr of the molecule?
Do you just look at the 2 biggest peaks for the fragments?

Reply 1306

Original post by Mus1995

Or transition element complexes. :smile:

Hey guys this is my first time doing F324. We do F325 first in A2 Chemistry at my school. I'm doing Chemical Engineering at Uni as I love Chemistry and Maths (love Maths and Further Maths).

I'm looking to get at least 85/90 UMS in this exam for my A* in Chemistry. It's tough but 2 years ago my brother easily got 90/90 so I'm hoping I can do the same. So far I've found the topics really short and easy. Made notes on most of the stuff in the book (that I felt I needed to write down) and done all the questions (spread, practice and exam), the exam quest booklets and 3 papers. First was a mock at school. I got 49/60 where 51 was an A. This was about a month ago though. January 2013. I made so many little mistakes mainly not drawing repeat unit polymers. Anyway now I'm doing papers and hitting the A* boundaries easily but lose out on the 85/90 UMS by 1 or 2 marks due to silly errors. It's literally because I stop thinking and make a really stupid mistake. Like not balancing an equation properly or reading the question. I guess it doesn't help I've been studying in an open environment (music, girlfriend etc) so after today I'm gonna go H.A.M and sit in my room on my own as I did before.

I wanna save some more papers until closer to the exam. So I'm doing the practice and examination style questions from the book again. Making notes on one or two things I forget/never understood.

Got S3 next Thursday. I took it as an extra module. Got 89 - S1 and 94 - S2 so it'll help me in general if I can swap it out for a weaker module. Also Statistics is a very fun and informative subject for me. All the new and efficient methods it teaches me about sampling and data. (It's 90% hypothesis testing).

C4 and F324 the week after. Then the week after that is FP3 which I need a C in to get my A* in Further Maths (without my S3 swapping in to help) and I'm done!

Hope everyone's revision is going well and you all reach your potentials. :smile:

June 2010 F324 was a bitch of a paper. The last question with the Hydroxyamines was awful for me. :frown:

Anyone wanna revise? Ask me some questions. Thanks! :biggrin:

Tldr; Stop every minute in every question and THINK. I feel this is the way to do well in F324. As long as you have the deep understanding and can think to identify the problems you can find the solution!

Posted from TSR Mobile

Thank you for taking the time to do this.

This was my Problem in January, my knowledge was great but I just blitz through the paper in 40 minutes.

I really appreciate these tips; yes it seems Chem 4 is more like Maths - The knowledge is secondary, but actually solving Stopping to think and solve the problems is much more important!!

Great stuff mate, thanks

Maybe I can give some input back in - I ALWAYS revise in a Closed Environment, I don't see the point in doing any Exam Questions unless it as similar to Exam Conditions as I can get - so definitely start doing that ASAP mate!

(edited 10 years ago)

Reply 1307

Original post by Gulzar

Wow you're an engineering student still doing A levels? How do you get such high scores lol...probably work really hard every day :wink:

I'm alright with f324 but it's the same problem with me where I make costly and silly mistakes when not reading the question properly or ruining the balanced equation. Do you have any tips on the mass spec questions like what to look for other than the M+ peak for the Mr of the molecule?
Do you just look at the 2 biggest peaks for the fragments?

I'm 18 in year 13. This is my first go on A levels I'm not redoing anything the only resit I've done was Physics 1 (Edexcel) in January and I went from 96/120 to 120/120 to bring my Physics AS from a B to an A. (Dropped it for A2)
Haha well listen to this. I didn't try that much in GCSE. Got an A* and 3 A's. AS I finished AAAB with around 85% UMS in the A's. Applied for Unis included Cambridge, didn't even get to the interview stage because my grades weren't good enough. Now I'm looking like I can get my predicted UCAS grades apart from Chemistry which is near impossible (3A*). All I did was improve my work ethic. I realised it doesn't matter how much time I spent studying. It was all about how effective and the timing. Ie during the learning process spent time consolidating stuff and for Chemistry read ChemGuide (gives you a deeper understanding). For Maths do every question in the book. By the time exams are a few weeks away you can consolidate stuff you don't remember or aren't good at and then hit papers and you should be pretty solid. I've done this in January and I've done it now and I'm hitting 90%+ in S3, C4. FP3 I haven't finished working on yet but I only need a C so it's okay. And it's on the 25th June. Before that my previous exam is 18th so I have a week to get it solid. Chemistry is being a problem because of my exam practice ethic (open environment) which stops me from thinking etc. So I don't work HARD I just work efficiently. :P

Mass Spec is pretty easy. At the end you have a large peak and a peak that is +1 to it that is around 10% the size. This smaller peak is ignored as it is just the natural occurrence of Carbon-13 in the original molecule (it has a small abundance). Then look at the big peak this is the m/z peak = Mr as you know. For fragments; look at the structure of possible products if you have been given them/formed them, with these try splitting the C-C bonds up in different location and seeing if any of those Mrs match up with your fragments. Also remember they are all IONS. If you ever mention a molecule you will lose mark. Sometimes no m/z peak is present. This is because the compound has COMPLETELY fragmented, if you understand this. I haven't actually seen much mass spec. The m/z is all you need. NMR and IR are a lot better for deducing a molecule. They are normally combined. :smile:

Sorry for the long reply.

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Reply 1308

Gulzar

Original post by Mus1995

I'm 18 in year 13. This is my first go on A levels I'm not redoing anything the only resit I've done was Physics 1 (Edexcel) in January and I went from 96/120 to 120/120 to bring my Physics AS from a B to an A. (Dropped it for A2)
Haha well listen to this. I didn't try that much in GCSE. Got an A* and 3 A's. AS I finished AAAB with around 85% UMS in the A's. Applied for Unis included Cambridge, didn't even get to the interview stage because my grades weren't good enough. Now I'm looking like I can get my predicted UCAS grades apart from Chemistry which is near impossible (3A*). All I did was improve my work ethic. I realised it doesn't matter how much time I spent studying. It was all about how effective and the timing. Ie during the learning process spent time consolidating stuff and for Chemistry read ChemGuide (gives you a deeper understanding). For Maths do every question in the book. By the time exams are a few weeks away you can consolidate stuff you don't remember or aren't good at and then hit papers and you should be pretty solid. I've done this in January and I've done it now and I'm hitting 90%+ in S3, C4. FP3 I haven't finished working on yet but I only need a C so it's okay. And it's on the 25th June. Before that my previous exam is 18th so I have a week to get it solid. Chemistry is being a problem because of my exam practice ethic (open environment) which stops me from thinking etc. So I don't work HARD I just work efficiently. :P

Mass Spec is pretty easy. At the end you have a large peak and a peak that is +1 to it that is around 10% the size. This smaller peak is ignored as it is just the natural occurrence of Carbon-13 in the original molecule (it has a small abundance). Then look at the big peak this is the m/z peak = Mr as you know. For fragments; look at the structure of possible products if you have been given them/formed them, with these try splitting the C-C bonds up in different location and seeing if any of those Mrs match up with your fragments. Also remember they are all IONS. If you ever mention a molecule you will lose mark. Sometimes no m/z peak is present. This is because the compound has COMPLETELY fragmented, if you understand this. I haven't actually seen much mass spec. The m/z is all you need. NMR and IR are a lot better for deducing a molecule. They are normally combined. :smile:

Sorry for the long reply.

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Wow that's brilliant thank you :smile:

So just gotta really focus on exam technique for chemistry :smile:

Reply 1309

Original post by Better

Thank you for taking the time to do this.

This was my Problem in January, my knowledge was great but I just blitz through the paper in 40 minutes.

I really appreciate these tips; yes it seems Chem 4 is more like Maths - The knowledge is secondary, but actually solving Stopping to think and solve the problems is much more important!!

Great stuff mate, thanks

Maybe I can give some input back in - I ALWAYS revise in a Closed Environment, I don't see the point in doing any Exam Questions unless it as similar to Exam Conditions as I can get - so definitely start doing that ASAP mate!

Complacency results in **** grades. (Got 77 in M1. I did M2 so thought of it as easy. Didn't work for it. Got cocky in the exam. Was messy etc) Like you are complacent so less stressed so you aren't under pressure to check your answers as you feel you are right. Feeling nervous and stressed is the best way to do well in an exam for me. Oh. And in maths WRITE BIG. Use all the paper you can. I've lost out on UMS because a marker can't read my working! (Sucks) You get unlimited paper so may as well haha. Same for Chemistry. Apart from the diagrams etc which are long to draw out again.

Yeah. Stopping. Reviewing the question again and actually thinking about what they want you to do. Some of the application is a bit tough but I think apart from that the content in this exam is pretty easy.

Starting today man. Thanks. :smile:

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Reply 1310

Original post by Gulzar

Wow that's brilliant thank you :smile:

So just gotta really focus on exam technique for chemistry :smile:

Read chemguide on the relevant stuff if you haven't! Just google it and it has all the OCR spec on there and it explains everything so well! :smile:

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Reply 1311

Zzzyax

perhaps someone can help me with a question, bromination of phenol produces a white precipitate, does this white precipitate also form with chlorination?

Reply 1312

Original post by Zzzyax

perhaps someone can help me with a question, bromination of phenol produces a white precipitate, does this white precipitate also form with chlorination?

ImageUploadedByStudent Room1370718379.428817.jpg

from the wiki page it says that it is a white/yellow precipitate.

It can only occur with Br2 or Cl2. As these can be induced by phenol to form the permanent dipole Br(delta+) - Br(delta-) and therefore the electrophile that can attack Phenol etc.

With HCl for example Cl(-) is formed. This is a nucleophile and cannot attack Phenol. The same applies to HBr.

It's not required for us to know about the above. The spec is only concerned with Bromine and Phenol.

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Reply 1313

Do we need to know the Actual Reactions and groups of Polylactic Acids etc etc ?

Reply 1314

Do we need to know the reaction of Biodiesel as well? Transesterification?

Reply 1315

Original post by Better

Do we need to know the reaction of Biodiesel as well? Transesterification?

Yeah Transesterification is on the spec. You just need to know that Biodiesel is produced this way. You take a triglyceride and react it with an alcohol such as Methanol or Ethanol with a NaOH (aq) catalyst to form Biodiesel and Glycerol (which is sold off to the pharmaceutical industry, increasing the atom economy of the process). Other conditions such as heat and reflux are not specified. :frown:

Biodiesel itself is simply an ethyl or methyl ester of a fatty acid. eg CH3 - O - C=O - R or CH3CH2 - O - C=O - R
where R is the fatty acid (From the triglyceride).

If you look at p35 in the book and the structure of the triglyceride, all it is doing is breaking the C-C bonds and sticking a Hydrogen there, so that's an easy way to remember its structure. :smile:

Regarding the polylactic acids, could you specify where in the book they are so I can have a look? :P Thanks.

(edited 10 years ago)

Reply 1316

dawg

Can anybody explain question 5b) on this paper please

http://www.ocr.org.uk/Images/131288-question-paper-unit-f324-rings-polymers-and-analysis.pdf

MS: http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

It's proton NMR, I understand most of it except for on the graph at around 7.4ppm, it suggests benzene is next to multiple hydrogens yet it is only next too a -CH2 group?

Reply 1317

Original post by dawg

Can anybody explain question 5b) on this paper please

http://www.ocr.org.uk/Images/131288-question-paper-unit-f324-rings-polymers-and-analysis.pdf

MS: http://www.ocr.org.uk/Images/135165-mark-scheme-unit-f324-rings-polymers-and-analysis-june.pdf

It's proton NMR, I understand most of it except for on the graph at around 7.4ppm, it suggests benzene is next to multiple hydrogens yet it is only next too a -CH2 group?

This peak is due to the Hydrogen atoms bonded to the Benzene. The splitting pattern occurs due to adjacent Carbons being bonded to Hydrogen atoms. Think about this. The adjacent Carbons are Carbon atoms bonded to the Carbon atom that is bonded to the proton responsible for the peak. Looking at the structure of the ester the benzene is bonded to another group of atoms at a single point. This creates distinct proton environments. However as Benzene is symmetrical these H - Benzene environments are identical. Therefore there is only one peak. The splitting pattern occurs because the H - (C) Carbon in brackets is bonded by sigma bonds to two other Carbons and a system of pi bonds to THE OTHER 5 Carbons! Each of which has a proton apart from the one that is bonded to the group of atoms. This causes the splitting pattern observed.

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Reply 1318

Can anyone please explain Zwitterions with different R groups and at different Ph's not sure I fully understand this?

Reply 1319