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Analysis of 2011 Chemistry 9647 Papers



Hi all,
 You are doing well. Keep up the good fight! JC2 is an intense year and you need good time management, focus and motivation to keep yourself going.



Cambridge seems to like alcohol reacting with HBr (conc sulfuric acid involved too). So pay attention to halogenoalkanes and alcohols chapter, and Grp 17 chemistry of how HBr is generated.

You may want to read about

stalactites and stalagmites. The formation is a little similar to 2010 Paper 3 Question 3.


http://science.howstuffworks.com/environmental/earth/geology/stalactite-stalagmite1.htm

You may also wish to read up on the effect of ligand strength on the colours and energy gap of transition metal complexes.

Also, you may like to prepare for tetrahedral complexes eg. [CuCl4]2- on how the d-orbitals are split and the energy gap. (my uni year 2 topic, taught by a grandpa prof)

You may like to clarify what are ppm (parts per million) units.

You may like to practise deductive  inorganic mole concept calculations. Be prepared for quite a lot of calculations in the papers (and insufficient time!!!!)

Also, you may like to look at Titration of phosphoric acid with sodium carbonate.

Also, Titration of diamine with hydrochloric acid.

You may like to look at diols and dicarboxylic acids.

Different allotropes (of sulfur and phosphorus)

How is nylon-6,6 formed?

Do you know ethanedioic acid (H2C2O4) can be oxidized to carbon dioxide?

Basicity of ethylamine, phenylamine and a tertiary amine.



You need to be very fast in tackling your A level chem papers. I heard some past students complain that they did not have enough time to finish the papers, I think especially Paper 3.
Which means you need lots of practice and to time yourself in normal day Paper 2 and 3 practices. For MCQ, some students skip the calculcation questions and maybe do organic chem questions first. It is up to you to strategise...

You may need to do a lot of deductive organic chemistry questions. Eg. An organic compound C12H22O4 (Just a hypothetical formula) undergoes the following tests: ...... Deduce the full displayed formula of the organic molecule. Last year, at least 28 marks of such questions came out.

Do you know the ion S2O8(2-)?

Cambridge may also ask about pKa of organic acids or pKb of organic amines.




I am happy and passionate as a tutor. I really love chemistry... BTW, we live in a biological and chemical world. The biological basis of life is still pretty much of chemistry. And chemists have to thank the physicists and the mathematicians for laying the foundations. Atomic Structure would be so incomplete without Rutherford and Bohrs!!!!


*************************************************************************************
Serious business section:

Cool man! Ready for the stuff? Let us go! You can overcome! You are resilient!!!


If you have the finances, you may like to source for prelim packages done up by teachers from a few JCs. Ask your friends in different JCs whether their teachers have shed some light on the assessments. You may like to post your comments below, just to share your insights with others. 21st century is about collaborations and networking!!!

[New] Determined students may like to cut down on social media and media usage. Multi-tasking with many media devices while you are studying are not proven to be beneficial.

It will be good if you can try putting away your handphones for a few hours per day while studying. Minimizing distractions is important. Hope you are not offended! The modern brain is not optimised for multi-tasking, as shown from psychological studies.

Resolve your relationships issues, be respectful towards your authorities. The modern generation has lost the art of honoring our authorities and elders, and there are consequences for that. No one is perfect in the world.








You may need to prioritise your time to see whether doing all these is worth it. You need to juggle your revision schedule and all your subjects.

[Those who are hardworking may like to go to your school library and check whether there are any books on practical organic chemistry experiments. There are precautions recorded in the books and general descriptions of the apparatus used in organic chemistry experiments, etc. Plus detailed experimental procedures on how to prepare eg. azo-dyes.

An interesting question : why are some organic compounds coloured, for example azo dyes?

[New] Do you happen to know what are the (cutey looking) centrifuge machines sitting in many (smelly???? fragrant?????) chemistry labs in NUS, NTU used for?


Get the basics first, ie. revise lecture notes and re-do tutorial questions. Next is to practise prelim papers.

You may like to grab hold of the three solutions books to Ten Year Series by different authors, and examine their answering techniques . Also, you may wanna relook at your school's tutorial answers and find out how teachers answer the questions in a concise yet power packed way.

One area students have done poorly throughout my years of teaching experience is in the area of answering technique. I was shocked when I saw the answer in the chapter of gases and liquids: "All gases have zero volume at r.t.p." when the candidate meant another thing.

So, brush up on our answering technique. There is some memory work involved especially in topics that you are weak in. Eg. you may need to understand and memorise the answer of "why are transition metal compounds usually coloured?" (This type of question seldom comes out nowadays) Understanding comes first, please take note of that. You can never memorise your way through in A level maths and science subjects.

The style of questions in exam papers are very tricky. Memory work does not suffice. You need to apply the concepts in a lively way to novel questions. That is why exposing yourselves to many scenarios of a variety of questions make you more prepared. Practice and applying creatively the right type of questions make perfect, together with your answering technique which include the *Key Words*. I scan an answer for key words and later for the whole context. Key words must be included. Some students are not able to spell Le Chatelier's Principle and this may create a negative impression in Cambridge examiners. Having good handwriting is also important, as examiners are marking during the cool winter and chilly and lonely? season. Plus, Christmas and New Year's Day they are marking. How would they feel? Make them happy!!!! Get what I mean?
.

****** You may like to have a study timetable to instil discipline upon yourself. Reward yourself occasionally with eg. sundae, Macs or Ajisen Ramen (whatever you like) when you accomplish something. I saw a JC girl and she was really focused and determined to take SATs to go US uni and get scholarship. Real driven...


Sorry for being long-winded.

[New] : You may like to look at Rod Beavon, Doc Brown's websites for clues. You may obtain the web addresses from BedokFunland JC's website.

  Do you know how to dilute a concentrated mineral acid?

Brief analysis of 2011 A level H2 Chemistry Paper from Cambridge-SEAB:


Chill man! Ready? ??? Can you still give me a hi-5 or you tell me secretly "Why did I get into the chemistry in the first place last year in JC1? Someone conned me into it!!!!" Just joking,,, Just joking. Chemistry does you good no matter how hard the journey seems. It is when you overcome a hill or a mountain that you appreciate your past journey.




 General comments: Organic chemistry usually takes up about 40%  of Papers 1, 2 and 3. Cambridge has the discretion to change the weightage of the different sections of chemistry. You are very likely to encounter organic drug molecules in your assessment questions in school.

Proteins questions are highly likely  to be set in your school assessments and Cambridge exams. Here is a fun proteins question : http://alevelchemistrysg.blogspot.com/2012/03/fun-protein-question.html






Those who are really kiasu (afraid of losing out) may look at other exam boards in UK past year papers, eg. Edexcel, OCR....

For SPA, listen carefully to your teachers in classroom to do well in your SPA assessment. Also, in tutorials, your tutor may give tips on what type of questions may appear in mid-year assessment. If your tutor is nice, you may approach him/her and ask him/her about the Cambridge exam reports on the previous 2009-2011 exams. You may like to look at the previous Cambridge international papers as some of the questions seem to be set by the similar team of professors. Pls refer to BedokFunland JC on my blog's side-bar for the website of Cambridge international exam papers.

[New] Do you know the nature of the chemical bonding in lead(II) and lead(IV) compounds?

Why does the element silicon not ***catenate*** like the element carbon though they are in the same Group?



**** As one of the examiners may have training in bio-inorganic chemistry, inorganic chemistry could have a larger share in the papers this year, which may mean that Physical chemistry may be reduced in weightage but with more calculations. It is only my guess. If your teachers are nice, you may like to ask them for tips and post the comments below, in the comments section. It does make sense to share our knowledge. When we give to others, strangely we receive something back in return, maybe in another form. Life is still mysterious, even as scientists stand on the shoulders of giants.

Do you know the chemistry in the old Kodak films of 1970s - 1990s film cameras?

Paper 1

- Electrolysis is often neglected in the chemistry syllabus, and there is one MCQ from 2011 paper on electrolysis.

- Candidates need to know the catalytic converter action of car engines.

- As we have pointed out in our previous year post, diazonium salts could come out. In 2011 paper, diazonium cation came out.

- Vinyl chloride does not undergo Sn2 reaction. Read up on a university organic chemistry textbook why it does not undergo Sn2 reaction.

- Alkynes : - bond character 
                   - geometry (using VSEPR theory; this is only a theory!        It has many limitations!)
                  - reactions

- One of the examiners may have researched on soya products chemistry. For 2010 and 2011 papers, soya products chemistry (eg. amino acids and certain phenols) came out.

- Heterocyclic aromatic chemistry eg. pyridine C5H5N
   (Bonding)

- By-products of Sn1/Sn2 reactions. This type of question came out for both 2010 and 2011 papers.

- Azo-dyes. We pointed out this out in last year's post.

- Why magnesium chloride in solution is slightly  acidic.

- Baeyer's reagent

Paper 2

- Acetic Anhydride

- Practical Organic Chemistry

- Purification and Recrystallisation in organic chemical reactions

- Group IV elements and their bonding

- Inert pair effect in lead(II) compounds

- Hoffman degradation of amides

- Ethanedioate ions and ethanedioic acid. How they can be oxidised by potassium manganate(VII). Titration curve of ethanedioic acid with a strong alkali such as aqueous sodium hydroxide.

- Different pKa values of dicarboxylic acids eg. HOOCCH2COOH. This kind of question has come out for 2010 and 2011 papers.

- This year for planning component, it is not known whether it may be an organic chemical experiment, or physical chemical experiment (eg. thermochemistry [ie. Energetics]) or others. Candidates are advised to prepare for an all-rounded education in SPA planning. 
You may source for planning packages from other JCs. 
If the chief examiner is an organic chemist, organic chemistry may come out again as planning component in Paper 2.

Paper 3

- Titration curve of a dibasic acid with a strong alkali. Candidates are expected to pinpoint the buffer regions, approximate or exact pH at various stages of the neutralisation, pH at equivalence points etc

- O=C=C=C=O (look at Paper 3 Question 2(c) for the context of this molecule)

- PCl3 and PCl5 were hot favorites in 2011 papers.

- 2012 papers may be sulfur dioxide and sulfur trioxide, or nitrogen, arsenic or selenium compounds or aluminium compounds

- Propofol, the hypnotic drug that contributed to the misadventure of Michael Jackson, the famous singer, may come out this year.

- Myoglobin, chlorophyll a and b may come out this year

- Crystal Field Theory in Transition Metals chemistry : Low spin state and high spin state

- Williamson synthesis : how ethers are formed

- Chlorine containing compounds came out frequently for 2011 papers.

- How does chlorine react with cold and hot aqueous sodium hydroxide?


-- simple chemistry of chlorate(I)  ions, ClO-. 

-- simple heterocylic aromatic chemistry.

-- Wikipedia anti-HIV drugs????

-- Intramolecular cyclization reaction of organic molecules [ie. the molecule itself has at least 2 functional groups which react with one another to form a cyclic product, to put it simply]

-- allotropes (eg. of sulfur, carbon, tin, phosphorus) 

-- why is iron(III) chloride solution acidic?

-- When do you use lithium aluminium hydride or sodium boronhydride in reduction processes of practical organic chemistry reactions? 

-- Amino acids, proteins and their entropies.

--End of analysis

Can you still give me a hi-5? Wanna watch some vimeo or youtube videos to chill a bit? :) Well, Chemistry is real demanding, and we need to prepare well...Well, life is not a bed of roses, anyway below the rose there are some branches and some thorns. 

You really need a very clear and alert mind as you tackle Papers 2 and 3.



<<For more secrets to scoring in A level Chemistry, try tuition with Mr Chong, the blog owner! Contact Mr Chong, the tutor, at HP: 98935144.>>

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