Wednesday, November 16, 2011

Tips for 2014 JC H2 Chemistry Students


[Updated on 1 Sep 2014]



[Under construction. Thank you for your patience!!]

Hi JC students and international visitors,

Welcome to my revamped blog post. I hope to deliver good and more organized information to you this coming year in 2014.

There are now section headings that makes it easier for you to navigate this post
If you decide to engage my tuition service, I may only deliver the higher order thinking materials when you are ready. Many students are struggling with the basic materials covered in JCs and need help in basic concepts. I can gladly help in this area. 

Section headings

  • Introduction
  • Biochemistry questions
  • Arrow pushing mechanism in organic chemistry
  • Organic chemistry  
  • Group IV elements and their compounds 
  • Group VII chemistry
  • Some topics to take note of
  • Energetics
  • Information for those aiming for a distinction in H2 chemistry in the year 2014
  • SPA planning on organic chemistry
  • Chemical Bonding
  • Exam revision
  • How to tackle organic chemistry
  • Optional Topics to Explore
Introduction

This blog may help JC ( Junior College) students in Singapore to cope with the Cambridge-Singapore GCE A level (H2) assessment. Organic Chemistry occupies a distinctive and important position in the Singapore Chemistry syllabus.

After your prelims, you may want to practise 2010 to 2013 Cambridge papers. (aka ten year series). You can also practise the earlier papers which are easier or the international Cambridge papers at xtremepapers.com

Press on!

You may be more relieved to know that 2013 Cambridge Chemistry papers were much easier than 2010-2012 papers and it seems that examiners did not ask much of out of syllabus stuff. I find that the examiners are quite unpredictable and I do not know of the standard of the papers this year. Usually one or two of the papers out of Math, Physics or Chemistry will be unusually tough each year. One tutor says that the papers will be as easy as last year, but I think that it may be just a little more difficult than last year's papers, and may be much easier than 2010-2012 exam papers.

One JC has claimed that it is not spotting questions for SPA planning in Paper 2. So candidates are reminded to prepare holistically for SPA planning, as Cambridge has been rather unpredictable in the last 4 years (2010-2013). So you may want to prepare for SPA planning more thoroughly after prelims 2014.

You may like to read up on:

 - selective precipitation (in a university general chemistry textbook such as Chemical Principles by Zumdahl. I like this textbook a lot.)

 - conjugation in 1,3 - butadiene.

These have appeared in 2013 Cambridge papers, so the trend may continue this year.

You may also like to explore isomerism in transition metal chemistry in the Zumdahl textbook, which is in university chemistry syllabus but may appear in prelim papers.

But it is not a time to let down your guard. Let us be consistent in our daily reading of lectures, and do our tutorials faithfully (I know that the sense of weariness of doing tutorials has set in; it is the time for half done tutorials in JC2; been there, done that before. But keep pressing on!!! You can do it and achieve it for your dream course in  university or some other routes!!! Sometimes setbacks can be a catalyst for even greater success, as a start-up entrepreneur shared in her latest book!!)

Do have a look at the standards of the International Cambridge Pre-U papers of 2013. [Note: these are not for Singapore students] The examiners have used research papers of 2010 and 2011 in their questions:

http://papers.xtremepapers.com/CIE/Cambridge%20Pre-U/Chemistry%20%289791%29/

Just hope that the standard of this year's papers will be lower than that of 2013 International Cambridge Pre-U papers. Note that these papers are tougher than the usual International Cambridge papers.

There have been many additions to the contents of International Cambridge Chemistry exam syllabus in 2016. Those who are super on can learn the new additions to prepare for your prelim exams.

2016 syllabus : http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20%289701%29/9701_y16_sy.pdf

Many JC teachers have taken materials from university organic chemistry textbooks and setting new reactions in the prelim papers beyond the scope of H2 and H3 syllabuses. So just be prepared!!


Ten year series solutions are now out in Popular bookshops. But just be careful about the quality of the solutions as the authors did not provide the most satisfactory answers to last few years papers.

Please pay close attention to organic chemistry topics, as this section is highly important. When you are ready for the challenge, you may want to reproduce summarised reaction charts (with reagents and reaction conditions) by functional groups of all reactions in organic chemistry. Hence, it makes sense to go to the library and get a book on speed memory techniques since lots of memory work (and more importantly, understanding) is needed for chemistry.

Remember, the mechanisms usually involves "nucleophile seeking a electrophile" or "an electrophile attacking a nucleophile". Take care of the electron flow that are depicted by the arrows.


Biochemistry questions

There is a new biochem examiner in the Cambridge exam board, and he/she may set question(s) in Paper 2 and 3. If your tutor is nice and hardworking, you may want to request your tutor to give you a few questions of biochem-reduced-to-organic-chemistry. Biochemistry is becoming very popular in the 21st century and it overlaps easily with organic chemistry. I just happened to be quite right as 2013 papers involves hormones, which are biomolecules.

Or you can hop onto your school library and find some latest organic chemistry university textbooks and scan through just a few biochem-related questions. Just a few will do as your time is highly limited.

A lot of the concepts in biochem are drawn from the foundational principles of organic chemistry.

A sampling of Biochemistry : Fats (triglycerides)

How are fats (triglycerides) formed? What happens when stearic acid reacts with glycerol? You may want to ask (Dr) Google and key in this acid and glycerol into the search box of Google.



Arrow pushing mechanism in organic chemistry

You may like to ask your tutor to teach you arrow pushing mechanisms in organic chemistry. This is only fully taught in year 2 NUS/NTU, and has been brought down to A levels in last year's exams. But I suspect your tutor has no time!!! You still need to tackle SPA Planning question! SPA question may be a complete surprise again this year. So there is no point for me in spotting the question. You may just need to prepare the topics holistically.

There is an organic chemistry textbook that is published in 2012 that is written by 3 authors, one of whom is a Cambridge University author. Since Cambridge University examiners set the exams, you may get some clues from this textbook.

Here it is:


Title : Organic Chemistry (2nd edition)
Authors : Jonathan Clayden, Nick Greeves, Stuart Warren
Publisher : Oxford University Press

You may like to briefly scan through it and get prepared to tackle higher order thinking questions in the exams. If you keep cool in exams and extend your knowledge of chemistry concepts, you should be able to tackle novel problems in the exams. This textbook is not written simply and is more targeted at university senior undergraduates.



Organic chemistry


You may like to study on chirality - meso compounds. This is in the H3 syllabus but it came out in 2012 H2 papers.

Mr Maverick Puah, a famous chem tutor in Singapore, has posted sometime ago on his facebook updates on crown ethers. I also favoured this last year, and there is a question which has an organic molecule that resembles crown ether in last year's exam papers. So you may like to wiki on it.


But you have to secure your basics first. These things that I mention are the optionals that give you an edge in chemistry.

The examiners are gonna set some NUS/NTU year 1/2 questions in this year's Cambridge papers. So there will be new reactions that you have never seen before in organic chemistry, but they will be an extension to what you have learned before. So keep cool and get your fundamentals right.


Cambridge may like such acids (which are biomolecules) in their exams:




oxalic acid           HOOCCOOH

malonic acid        HOOCCH2COOH

succinic acid        HOOC(CH2)2COOH

glutaric acid         HOOC(CH2)3COOH

adipic acid           HOOC(CH2)4COOH

pimelic acid         HOOC(CH2)5COOH
  
 and also adipic acid, tartaric acid etc.

<<For more secrets to scoring in A level Chemistry, try tuition with Mr Chong, the blog owner! Contact Mr Chong, the tutor, at 85862339.>>


If Cambridge employs new examiners this year, the style will change drastically again. Be prepared for uncertainties in the chem exams!!




Organic Chemistry questions are highly likely to take up more than 50% of your prelim exam papers. So prepare adequately for them. Physical chem questions maybe occupy about 30%. This is just a rough guide as it varies from JC to JC (Junior College).

You may want to ask your teacher nicely to give your class many organic chemistry elucidation questions. The examiners favor structural elucidation problems in organic chemistry. You can find some problems in past S papers (the H3 equivalent before the year 2005). So, you may like to request from your teachers for some S papers.




Also, if your class is game for challenge, ask your teacher, if appropriate, to teach your class some H3 / old syllabus S paper / university 1st year organic chemistry. Cambridge is literally operating without a syllabus nowadays. Anything up to PhD level materials can appear. So be prepared. I am just concerned that Cambridge may suddenly increase the level of difficulty in physical chem questions this year. By what means? They just select  some questions from 1st year university textbooks and modify them. It is really an uphill task for students. So master your basic materials and be prepared to do more to get a distinction. BTW, the students before 2008 had it so much easier....


I noticed that since 2010 exams, examiners have been using university organic chemical reactions in papers. There are also functional groups taught in university level , just for an example: thiols, -SH. Examiners can set the exam paper in a contextual situation. If the examiner continues the same trend, organic chemistry is going to be atypical this year. So an examiner may take a recent university organic chemistry textbook or his own research interests, then finds some functional groups not in A level syllabus. Next, he finds some reactions in the textbook, and sets the problem. By ther way, medicinal (drug) chemistry and biochemistry may be the hottest trends right now.


If I am not wrong, a certain government recently used chemical gas to poison some people in their country. The chemical may be sarin gas. You may like to wikipedia for sarin's molecular structure. Cambridge examiners may use news source as inspiration for setting this year's papers.


My ex-student who has gotten a Masters in Chemistry did not know of last year's chem papers, but yet told me about the optical activity of tartaric acid when I asked him to suggest two A level questions. Tartaric acid came out in last year's Cambridge papers and he was spot-on.

Another question he suggested was on enzymes. So you may want to study Chemical kinetics - enzymes and also proteins in organic chemistry. Sometimes, intuition can prove to be better than logic.

Lol.....


Those who have a little time to spare and are game for the challenges, you may desire to practise John McMurry's Organic Chemistry textbook questions, especially those of the later chapters, eg. hydroxy compounds, ***** carbonyl compounds (real important topic!!) ***** 

 You are still up to the challege!!! Our brain structures are complex enough to adapt and generate new neuro-connections.You may want to ask your teacher to teach you about resonance. It is out of syllabus but this term appeared in MCQ 2012 Cambridge exam papers.
Also, if your teacher did not teach Williamson ether synthesis, please learn it as Cambridge simply adores it.

Group IV elements and their compounds

There is an old nostalgic examiner who set one of the questions of Paper 2 of Cambridge exams last year. So, they may bring back contents from the old syllabus 10-20 years ago. Already, in 2015 syllabus of Cambridge International (UK), Grp IV elements are back in syllabus, after a long hiatus and disappearance from the syllabus 20 years ago. So you may like to look at the 2014/2015 syllabus at www.cie.org.uk    It gives some clues of the recent trends in Cambridge.


Group VII chemistry

Pls take note that Cambridge really likes Grp VII elements topic. Though inorganic chemistry seems to be memory work all the way through, there are some trends and tricks to take note of.
  

** A level chemistry tuition is available. Pls contact (sms) Mr Chong at 85862339 or  e-mail me at chemguide7@hotmail.com. More 'secrets' to reveal in my coaching sessions.


Some topics to take note of

 You may like to revise chemical bonding (a tricky topic), energetics (an important topic) and organic chemistry if you school has started on organic chem. As there is great continuity in the topics for organic chemistry, the minimum you can do in your free time is to revise your organic chemistry, as next year's lectures in 2014 will be booming at higher speeds.

 For those schools that did ionic equilibria, it is a very difficult topic. So revise it and practise a few questions here and there.

You can also do mind maps for some of the topics you are unsure of. Using analogies, similarites and differences can be another method to ensure your learning. Ask your school mates for ideas. Collaboration is the key in the 21st century world.



Energetics


  Please study the section on entropy changes and Gibbs Free Energy thoroughly. School examiners and Cambridge examiners may like to set questions on this section.





International Cambridge exam papers


International Cambridge 2012 exam papers are out in xtremepapers.com   You may like to scan through the papers and analyse the trends that the examiners are laying out. The Cambridge Pre-U papers are also out, and are tougher than the traditional Cambridge International papers. Your papers will be more difficult than International Cambridge papers 2012.


If you have the time, you may want to practise the latest International Cambridge chemistry papers at xtremepapers.com , just in case Cambridge sets similar questions from that paper. BedokFunland JC tutor has claimed that Cambridge modified some of the International chem papers of 2010 and 2011 in Paper 2 and 3. If you like  to attempt International Cambridge papers, which is of a slightly different syllabus, and generally much easier than Singapore papers: the website is here: xtremepapers.com

I am not sure of the safety of the website, which may have malwares.


I think I mentioned [CuCl4]2- ions a few years ago in this post; Cambridge may have set a similar ion [PbCl4]2- in either Paper 2 or 3 in 2012 papers.


Practical Applications of Chemistry

I was curious and googled on LCD screens. Your older LCD screens may contain the toxic gas nitrogen trifluoride (NF3). Try drawing the Lewis structure of one molecule of this. Illustrate with a diagram why one molecule of NF3 forms intermolecular hydrogen bonding with a molecule of methanol. Why does NF3 form in a 1:1 ratio with BCl3?


By the way, someone in Russia mistook methanol for ethanol, and drank the methanol. He was rushed to hospital. Methanol in sufficient quantity can make one physiologically blind.

Talk about funny and dangerous chemistry. So, anything wrong with the environment, it must be due to the chemists....






-- Older post written in 2011-2012; revised in Dec 2013  


Information for those aiming for a distinction in H2 chemistry in the year 2014:

This section is a joint project between BedokFunland JC (http://infinity.usanethosting.com/Tuition/) and myself.


Thank you BedokFunland JC for your invaluable advice!

 


SPA planning on organic chemistry

  An experiment on extraction of organic molecule citral from lemongrass. Partition coefficient and solvent extraction are involved. You may want to scan through the theory and look at the procedure:

http://spot.pcc.edu/~chandy/241/steamdistillationnew.pdf


 Another experiment on extracting an organic compound from nutmeg:

http://www.buzzle.com/articles/extraction-of-trimyristin-from-nutmeg.html
 

For the extraction of caffeine (a possible Paper 2 planning question), pls look at : https://teach.lanecc.edu/thompsonj/CH241/laboratory/Caffeine%20Extraction.pdf


Chemical Bonding

 Do you know how to draw the Lewis structure of HgC2N2O2? Wiki for mercury fulminate to check the answers.


 
Exam revision

 Maybe you like to do the Cambridge exam papers from 2007-2013. If you can grab hold of the prelim papers 2013, you may like to try a few of them too.  Can you pick up any trends?

 Maybe the strategy now could be to brush up on the theory aspect of weaker topics and to practise lots of Singapore-Cambridge exam papers, and a little prelim papers (if you can grab some 2013 prelim papers, if not 2012 papers).

 All the best to your exams! Revise your theory topics and SPA topics, and practise Cambridge-Singapore papers, starting from the latest papers to the earlier ones.

Group VII elements
 You may like to study the effects of dilute aqueous ammonia and concentrated aqueous ammonia on chloride, bromide and iodide ions. This is found in the chapter of Group VII and also ionic equilibria.

Miscellaneous information

 Chemical equilibria is very likely to come out, and it may involve Kp of gaseous systems.

 Will Cambridge like H-O-N=O? Or HClO3? Or CNBr? Or H2C=N-H? Or Br-CN? Or NOCl? Or C2O4 (2-), HC2O4(-), H2C2O4? Or AgIO3? Or HClO4? Or Ag3AsO4? Or NH2OH?

 Not sure whether global warming may come out in exams? Do you know the greenhouse gas (GHG) nitrous oxide (laughing gas) N2O has chemical structure N=N=O? Try working out the dot and cross diagram. Can you name three greenhouse gases?

 Are there anything special about the bond lengths of the C-C and C=C bonds in buta-1,3-diene? Wiki- about this molecule. (Topic: delocalisation of electrons in diene compounds)




Heating magnesium carbide in nitrogen produces magnesium cyanamide:

MgC2 + N2 --> MgNCN + C

Draw the dot and cross diagram of C2(2-) ion and cyanamide (NCN(2-) ion. "

Do you happen to know the dot and cross diagrams of cyanate, isocyanate, thiocyanate, chlorate(V), chlorate(VII), chlorate(III) ions, iodic acid and hypobromous acid? Wiki for these species.

How about types of hybridization of non-hydrogen atoms in CH3CN and HN=NH molecules?

Compare pKa of EtNH4+ and Et3NH+ ions where Et stands for an ethyl group.

 Carbon suboxide, or tricarbon dioxide, is an oxide of carbon with chemical formula C3O2 or O=C=C=C=O. (Courtesy of www.wikipedia.org) Will Cambridge like such molecules? It has come out before in the papers. It is your guess and my guess. 


 You may want to look at spider silk (a protein that has beta-pleated sheets).

Spider silk
http://www.chm.bris.ac.uk/motm/motm.htm
http://www.xs4all.nl/~ednieuw/Spiders/Info/spindraad.

Optional : ** You may wikipedia on "Zinc as an enzyme cofactor ", "Partition coefficient" in chromatography, "biofuels", "Ion channels in biological membranes", "Sickle cell anaemia", "Plastics that conduct electricity or emit light", ****"Ionic Liquids"******.






 You may want to google for Ni(CO)4 (nickel carbonyl complexes).


 Tell yourself you are intelligent and you can conquer all the papers. Be Prepared!!!

A trick about organic chemistry


  For organic chemistry mechanisms, you need to learn them well and reproduce them almost perfectly in the exams. Organic chemistry is understanding first, then memory work is next. In a chemical reaction, first understand which functional groups are changed as you go from reactants to products, and identify the nucleophile, electrophile or free radical, and check whether it is a substitution, addition, elimination or etc.... reaction. Lastly, it is to memorise the reaction conditions and catalysts. There are usually reasons why certain catalysts are used in certain reactions.



How to tackle organic chemistry

For organic chemistry, first understand the mechanism behind the reaction, then check the before and after (reactants and products) to see the which atoms or functional groups have been changed. (A little like the slimming ads where you compare the person before and after slimming. What changed before and after????) Lastly, understand why the reaction conditions are used. Then, "memorise" the reaction conditions. Many of the reactions require heating or reflux.

For some chapters, you need to know the details of the mechanisms very well. It requires some knowledge of nucleophiles, electrophiles or free radicals and the electron flow (eg. electrophilic or nucleophilic attacks). Next is to know whether the reaction is an addition, substitution or elimination or even redox reaction. (or other types of reactions)

After understanding the reactions, next is to commit into memory the reaction conditions and to practise as many questions as possible.

 I went to National Library on a hot and humid afternoon and scanned through about 10 issues of Nature journals published in 2010. Cambridge examiners may draw ideas from these issues.

What I found was that the main articles that were of interest are of the following topics:

Nanoparticles (nano-ribbons, nano-wires, nano-clusters)
 - Iron, Indium, Arsenic, Gold, Silver nanoparticles

Atmospheric chemistry

Semiconductors

***** Graphene (an allotrope of carbon. I suggest you wikipedia on graphene, it is a little similar to graphite)

Enzymes and proteins in biochemistry and medicine

You may try to source for Cambridge International Chemistry Papers 2011 and even Jun 2012 if they are available. Clues can be obtained from there.

I have looked at Nature.com, a prestigious journal on science and medicine, and I found that in April's issue, liquid crystals were featured in that journal. Basically, the concept is that an organic molecule can interconvert between one isomer into another, and (uv) light absorbance is altered as the conversion is done. This is one way that liquid crystals can be made. Nowadays, many spectacles can change its tint when exposed to sunlight. I believe it works by a similar principle.


Miscellaneous advice



You may like to look at bio-inorganic molecules, such as haemocyanin, myoglobin, haemerythrin, cytochromes P-450 briefly as I suspect that one of the examiners has training in bio-inorganic chemistry. Please use wikipedia or refer to an inorganic chemistry textbook in National Library or your school library.

**** Drawing inspiration from Rod Beavon's chemistry site, you may want to look at esters, fats and oils. Also, you may like to scan through Nuclear Magnetic Resonance Spectroscopy (NMR) and Infra-Red Spectroscopy (IR) theory. Cambridge set questions based on this website in 2010 and 2011 papers.





For 3 challenging exam style questions (mainly on organic chemistry, pls see : http://alevelchemistrysg.blogspot.com/2012/03/fun-questions-inspired-by-research.html )

For a  fun proteins question, please refer to my blog's side-bar. Proteins are almost 100% guaranteed to appear in your school's assessment or in the national exams.



OPTIONAL TOPICS TO EXPLORE

Good Knowledge to learn if you are aiming for a distinction in chemistry:

Stay cool! (: It is a long list, but you may just want to study some topics. Chemistry fanatics may spend much more time on the advanced A level topics!


Cambridge may set questions based on compounds found in soil and rocks.
A soil question came out in O level chemistry exams in 2011.


Simple Question : A university chemistry team has synthesized a new phosphate in 2011 with this formula : KCuFe(PO4)2

If the charge on copper ion in this compound is +2, what is the oxidation number of iron ion in this compound?
(I found this journal in NUS library! A lot of gems in NUS, NTU and even National Library!)




Physical Chemistry:
Ease of overlap of 2p vs 3p orbitals to form pi bonds 
(eg. N2 vs P4, CO2 vs SiO2)

Effect of percentage s (or p) character on C-C sigma 
bond lengths
pKa of amino acids and how they protonate/deprotonate in acidic/alkaline medium

Unit cells - found in chemical bonding of textbooks. It is out of syllabus but came out in 2011.

Fuel cell – practise prelim papers for novel fuel cells (including hydrogen fuel cells) (Electrochem chapter)

Bond length, delocalisation of electrons in resonance structures , hybridisation

Formal charges in drawing Lewis structures - chemical bonding (came out in 2011 exam papers)

Simple Molecular Orbital Theory in Chemical Bonding

*** Isotopes of hydrogen

Nuclear chemistry – alpha and beta radiation. Out of syllabus but appeared in exam paper. Nuclear reactors in Japan – how iodine-131 is formed. This chapter is found in Peter Cann and Peter Hughes "Chemistry" textbook.

Practical physical experiments – eg. Enthalphy change of reaction, kinetics

Solubility of Group II hydrogencarbonates, carbonates, hydroxides and sulfates. (Inorganic chemistry)

Reverse Osmosis and water treatment


Nernst Equation in Electrochemistry

Inorganic chemistry:

Transition metal – absorption spectrum, colours of transition metal ions and their compounds, eg. Colour of [CuCl4]2- complex. (Cambridge loves this!) Reaction of copper(II) ions with dilute and concentrated hydrochloric acid. Colours and chemistry of manganese, iron, vanadium and chromium compounds. Colours of complexes came out in 2011 and 2013 exam papers.

Crystal Field theory (strong vs weak field ligands, 
high spin vs low spin complexes)

Practical inorganic experiments – eg. Gravimetry Analysis (Nickel ions with EDTA4- titrations)

Fullerenes, buckminsterfullerene, carbon nanotubes (found in general chemistry textbook), graphene

Simple Nanotechnology (simple knowledge will do)

* Clock reactions in chemical kinetics

Ellingham diagrams in Gibbs Free energy and Entropy

Phase diagrams

Mass Spectrometry

Enzyme Inhibitors, Enzyme co-factors

Micelles (Bonding and forces of interaction)

***Diagonal relationships (eg. between Beryllium and Aluminium)

Organic Chemistry:

***** Practical organic chemistry – eg. How Reflux process is actually done, separating organic products from their impurities, apparatus for performing organic experiments, how aspirin is manufactured

Grignard Reagent – Organic chemistry. Read up in an organic chemistry textbook

Destruction of ozone by CFC mechanism in the chapter of halogenalkanes

Polymerisation – Organic chemistry. It is out of syllabus but appeared in 2010 exam paper

Reaction of halogenoalkanes with sodium ethoxide (also E1 / E2 versus Sn1 / Sn2 reactions); Williamson Ether synthesis

addition-elimination mechanism for nucleophilic acyl substitutions

Enols & Enolates (iodoform mechanism)

Imines & Enamines (2,4-DNPH mechanism)

Nucleophilic Acyl Substitution (addition-elimination mechanisms involving : esters, amides, acyl halides)

Ethers & Epoxides (mechanisms)

Organic Chemistry Redox reactions (mechanisms for reduction, oxidation states within organic compounds)

Azo-dye formation and diazonium salt formation (mechanism)

******* Arrow pushing in organic chemistry mechanisms

Dienes (resonance and bond lengths)

Acetic anhydrides

Hofmann degradation of amides (Came out in 2011 Exam Papers)

Friedal-Craft alkylation and acylation of benzene (including mechanisms)

Diels-Alder reaction (found in university organic chemistry textbook from your school library)

The differences between reducing agents such as LiAlH4, NaBH4 and hydrogen gas with nickel / palladium / platinum catalysts

Conformation of cyclohexane (found in organic chemistry textbook)

Alkynes and sp hybridisation

Green chemistry

(Cp)2Fe where Cp is cyclopentadiene

Melamine and DEHP -- food scare in Taiwan in mid-2011


2011 P1 Q27 "Nucleophilic acyl substitution of Amines 
unto Amides" (mechanism)

Ylides and the Wittig Reaction (mechanism)

Fries rearrangement (mechanism)

Hofmann rearrangement (mechanism)

Aldol and Claisen condensation reactions (mechanism)

Huckel's rule


Electrophoresis of Amino acids (migration to cathode vs 

anode) based on their Isoelectric points

Biochemistry:

Simple knowledge of structures of glucose, sucrose, carbohydrates, DNA, lipids

Haemoglobin (including iron(II) ions in haemoglobin) and chlorophyll

ATP and ADP and their roles in biochemistry - simple knowledge will do


Miscellaneous:
Group IV elements and their chemistry - inorganic carbon chemistry is getting important.
Graphene
Manufacture of sulfuric acid
Semiconductors
Solar cell materials
Ceramics
Free radical organic polymerisation reactions and their mechanisms

Some general advice

Work life may be more challenging than school life in the Shenton Way area; so cherish your study life. Global situations are really unpredictable in the 21st century. With you going to the workforce in the next 4-7 years, will Singapore still be competitive in 2020?

Listen to your passions and heart. What is your path after A levels? Success in life is about finding your sweet spot and developing in your passion area. A doctor or a teacher or an artist can be very happy serving in a rural area and earning little money.


Be adequately prepared. My advice is to have sufficient sleep the day before chemistry exams and be prepared for surprises during the exam. Keep cool, dudes!!!

 

Let me clarify my stand on JC lecture materials and the Copyright Act. The Copyright Act is grossly outdated and some author have argued for an overhaul of the Copyright Act in US in the internet age. With Google and Coursera, my idea is that if every JC puts their lecture and tutorial materials on the website(s) for all to view, students' standards should theoretically be raised. I feel that knowledge should be shared and collaboration is the key to success in the 21st century of uncertainties and seismic changes.

You may desire to analyse the trends in the Cambridge papers of 2010-2012, as your teachers may set questions that are similar to the papers in the prelim exams. Organic chemistry may be extensively tested in May/Jun/Jul 2013.




Set goals for what we want to achieve this year. Set your sight on greater things! Most of your parents and teachers have prepared you well for education, and the rest is for us to overcome hurdles! Next is to be consistent in little things. Your daily habits will determine what your end journey at JC will be. Have an overcoming attitude! Let us be strong!

An important thing is to grasp the gist of every lecture and tutorial. 

You may like to do some physical exercises to prepare yourselves for a challenging year ahead! Also, Being emotionally healthy, eg. not bearing grudges, does help you indirectly in studies as you can concentrate better in studies. Do not worry, be happy!!!! :-)

You can do it! You can surmount the barriers and fly as an eagle in 2013! Your dreams can come true! 

Do plan your CCA activities well, as CCA records are needed for entry to universities and some faculties need good CCA records. Well, it is not just points and grades in CCA. More importantly, is to have passion in your CCA and not just go through the motions. We only have one life, so live it well and to the fullest. :)
 
   What can you do for chemistry? Do you still like chemistry and your chemistry teachers? One important thing is to befriend chemistry and like chemistry and have some passion for this subject, even if you may not touch it the rest of your life after A levels.

 A good way is to make your own notes, or at least underline your notes. Some of my students draw cute cartoons here and there in their lecture notes....

 All the best! Network with your classmates. You are bound to need help from them at some point or another. Life is mostly about treasured relationships. Grades are not everything. I just wonder what Socrates said about education?????



Time management is crucial in this hypercompetitive education system.

You may want to have sufficient sleep before the each Chemistry Paper. You need a very clear and alert mind for the atypical questions in Paper 3.
 If your school has not finished the entire chemistry syllabus in mid-May, you may want to read ahead so that you could be adequately prepared for prelim 1 and prelim 2 exams. I know life is very stressful in JC, and this is the price we have to pay for having one of the best education system in the world. So play the game, pay the price and you will be amply rewarded. For those who just wind down from your fun CCAs, pls study very soon as it is late already. If you start studying only in Jun, it may be too late. This is a reminder, and a gentle one! (From one who has seen at least 1000 students go thru this system).

Anyway, how does one measure success? In terms of money, status and power? Is that the right way of measuring people? This question begs a debate. Our Singapore system may have too narrow a definition of success.


The bar for tests and exams has been raised. But say you can! You can! You can! Just do it!

Answering technique


All the best to your Paper 3! Pls read through all the 5 questions carefully and eliminate the question which you feel you may not score very well in. Time management is crucial. You need to be concise in your descriptive answers and yet the key words have to be in the answers. Do the calculation questions carefully as the different parts of the question are usually interlinked.

To prepare for Paper 3, you may want to read some of Ultimaonline (aka BedokFunland JC) website for some of the FAQs. These questions are reflective of the latest trends of Cambridge questions. His answers are generally pitched at JC2 and NUS/NTU undergrad year 1 standards.

His website can be found at the right side-bar of my webpage. All the best!


I have uploaded some questions for both JC1 and JC2 students.

URL:
http://www.scribd.com/doc/127310887/Mole-Concept-Question





We can learn from sports psychology. Michael Phelps, the great swimmer, psyches himself up before every race. So, similarly this A levels assessment is also a mind and psychological game. Even if the exam is tough, psych yourself that you will be     tougher     than the others. You have the resilience. Confess good words. Declare yourself a victor and celebrate (a little) victory even before the exams is coming. Being emotionally healthy is highly important. Inject yourself with doses of good and inspirational words : "I will conquer! I am a victor!"

For those who are a little knocked down before, get up. It is time to get up. Time is precious. Redeem the time. Get up! And keep fighting! Surround yourself with positive people! It is a mind game. Get up and start fighting. It is a mini war. Like a boxing match, the one who lasts the longest and is not out of the ring wins. Get up!

There are motivational books and inspirational websites. Get your morning happy. Mornings are the most crucial moments of the day. Get yourself psych up. You know the methods yourself.

Some students sabotage themselves by telling themselves subconsciously they do not like a particular subject. It is no wonder they do not excel in the subject. Excellence begins in the mind-set and paradigm. You can do it.... Just do it.... And do the right thing....!!!


If you can finish all of 2013 prelim papers of many JCs, the chances of you getting an A or a B may be higher. It is all about making few mistakes in exams and getting the right answers for the examiners that matter. Interpretation of question is an important key to scoring in the exams. We need not be long-winded in our answers. (You may find me super-duper long winded, haha....)


You may want to purchase HCI Organic Chemistry Summary booklet or do summary reactions for each functional group in organic chemistry.

Revision technique


******* Understanding chemistry is not to memorise the whole chunk of notes. Smart students ask themselves what the concepts are: eg. electron flow, arrow pushing, guessing which gases or other products are generated in a chemical reaction (smart guess), summarizing notes in their own words. Some students think of wacky short-cuts to help them remember concepts. (Thanks, Adam Khoo LTG!) Also, a visual learner may use a lot of highlighter and mind-maps, diagrams, tables and charts and summary of reactions and their reaction conditions to help them remember.

One of my students who was hungry for success remembers by keywords and association (neuroscience technique). Ask your smart classmates for some tips. Be nice!



A very useful advice from rsc.org (a chemical society) for tackling Paper 3 of Chemistry exams:

"Some of the questions will contain material you will not be familiar with.
However, by logically applying the skills you have learnt as a chemist, you should be able to work through the problems. There are different ways to approach the tasks – even if you cannot complete certain parts of a question, you may still find subsequent parts straightforward. "

*** For those JC2s who are really struggling in chemistry, please try to get your foundational topics right. Ask for help from your classmates. You may also want to seek help from tuition centres or private tutors or internet forums. Or e-mail to openlectures.sg and ask if the scholars can help you. Please start to revise now! Time and tide wait for no man!



Confess good words and positive thoughts.

Religion is a powerful force. Those who are open can seek help from the Person Upstairs.

Thank you everyone for journeying with me in 2013. What a year! May it be an enriching year for you.

May 2014 be a great year for all of you!


It is my pleasure to serve you all in these blogs.



All the best for your future endeavours!


For tuition enquiries, please call Mr Chong at 85862339 or email him at chemguide7@hotmail.com

   
Some textbooks to recommend:

You may refer to Bedokfunland JC’s website for some recommended textbooks.

Here are mine:

A-level Chemistry by Ramsden

Chemistry for Advanced Level by Peter Cann and Peter Hughes


University Textbooks :

Organic Chemistry:

Organic Chemistry by John McMurry


Title : Organic Chemistry (2nd edition)
Authors : Jonathan Clayden, Nick Greeves, Stuart Warren
Publisher : Oxford University Press

General and Physical Chemistry:

Chemistry3 by Burrow, Holman, Parsons, Pilling, Price

Optional : Inorganic Chemistry:

Inorganic Chemistry by Catherine Housecraft and Alan Sharpe

chemguide7 aka Mr Chong
Private tutor
ex-MOE teacher
B.Sc(Hons), Dip in Education
E-mail: chemguide7 at hotmail.com
HP : 85862339

http://alevelchemistrysg.blogspot.com


God bless you!! 


P.S. The more you are exposed to chemistry concepts, the more you understand the paradigm of the scientists. Make chemistry a delight, not a duty or a chore. And you will score well. Be curious! Do not worry, even if you do not read any of these topics, you can still keep cool in exams and solve the problems. You just require more thinking on the spot!

You may use wikipedia to read more about the topics mentioned above.

# Mr Chong is not responsible for any inaccuracies or the topics he highlighted that do / do not appear in assessments. Chemistry knowledge is vast and examiners have a large scope to test for in exam papers. 







3 comments:

  1. If I am not wrong, a compound similar to acetic anhydride came out in Paper 3 2012 Papers. I did mention iron compounds in transition metals and it came out in Paper 3 too.

    ReplyDelete
  2. These site have proven awesome for chemistry tuition.Detail information as per different level are given and tutors are excellent.

    ReplyDelete