2017 H2 Chemistry JC1 & 2 students post your questions here
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Taiwan : http://wenr.wes.org/2016/06/education-in-taiwan
Indonesia : https://link.springer.com/article/10.1007/BF00598171
Malaysia : http://multilingualmania.com/english-or-national-language-thoughts-from-malaysia/
Are you kidding? The best language of instruction (eg. when learning Chemistry, Physics, Biology, Medicine, etc) is obviously English, the lingua franca of the world, in order to effectively communicate with the rest of the world (ie. not just with America ; for instance in Europe, the many different Europeans all have their own distinct mother tongue language, but almost all are at proficient in English for the sake of communication with the rest of the world). Having English as the language of instruction has conferred the single most important educational advantage Singapore has had over other Asian countries (eg. Malaysia, Indonesia, Taiwan, Hong Kong, etc), and as Singapore's bilingual policies have proven, does not necessarily require sacrificing your mother tongue or ethnic culture altogether.
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A BedokFunland JC H2 Chemistry Challenge
99% of Singapore JC students will get this wrong, and about 50% of private tutors and school teachers will get this wrong.
Calculate the pH of 1.0 x 10^-8 mol/dm3 of HNO3.
Go ahead and calculate it, and if you like, post your final answer here to 3 decimal places (note : don't show your working, coz in case you get it right, don't ruin the fun for others). I'll only state if your final ans is correct or wrong, nothing more nothing less.
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This is a repost from 2013, but I just wanted the new JC students to know about this. Back in 2013, a RJC student named Kevin Wee, burnt his A level certificate in his bedroom, and video recorded the burning on YouTube, together with a 4 hour verbal exposition on why he did this, together with his personal take on the Singapore Education System, and on being a student in Raffles Junior College. It's a pity the video has since been taken down (he must have kena a lot of threats). At that time, Kevin posted about his experience and his A level cert burning video, on many different Singapore forums on the internet. I'll reproduce one of his posts here (the one he sent to TheRealSingapore), together with RJC Confeesions Facebook link, and Kevin's Facebook link.
My name is Kevin Wee, 19 this year. I hope you will take some time to hear my story. I was from Victoria School (VS) and Raffles Junior College (RJC). Growing up, I was taught to work and study hard, for it will give me a secure and good future. I excelled in sports and studies, working extremely hard at both. I never had time for a relationship and spent little time going out with friends. I played badminton for VS in sec 1 and 2, and switched to tennis in sec 3 and 4. I achieved a national ranking, which helped me get into RJC through DSA. In RJC, we won a double gold and I represented Singapore in the ASEAN schools games in 2012.
I had everything going for me, and just needed to work hard for A levels, get good grades, and get into medicine. Or so I naively thought. 1 month before the A levels, there was construction above my house. I got nervous and agitated, but managed to compromise and study 14 hrs a day for a month.
First day of As, I was placed at the side of the hall where I never sat before and the aircon was blowing in my face. I have asthma, and I couldn’t breathe properly. I got shifted to a ulu place whr I got distracted by some sounds (prob due to the anxiety) and ""scrwed up"" GP. I went into mild depression and couldn’t concentrate on the following papers (kept worrying where ill sit) I didnt sleep at all before math, and had a complete mental block in both papers, when to the toilet and sat there...handed up 2sheets of paper. Aft that, I wanted to withdraw, but my mum encouraged me and took me to the doc and got medication. I struggled through the rest of the papers...trapped by my thoughts of the future and all kinds of weird sensations that distract me. I barely made it through As and I thought it was going to be fine.
I was wrong. I had death thoughts (of myself getting hanged, getting cut up,etc) and I couldn’t sleep or control them. Aft 4 days of no sleep, I honestly thought without a doubt I was going to die. I was admitted and the doc gave me a sedative. It didn’t work. I lay awake for 4 hrs, and then woke up trembling from head to toe, I called my parents and said ""goodbye"". The doc gave me a stronger sedative and I fell asleep.
Anyway, I was stuck in depression for 4 months...I was suicidal in January. Some of you may be thinking, exams are a very stupid reason to go into depression like that, but it wasn’t my fault per say. I had dreams, I studied exceedingly hard for so many years. To me, my future was gone to trash, all my hard work over 18 yrs rendered useless. Furthermore, my mind was too spent from all that studying and it shut down because it had reached its limit. Depression is as much a physical as it is mental illness.
Somehow, I recovered slowly. In late march, with medication, love, support, and letting go of everything. I told myself, I really don’t need a degree to survive, there are other ways to make ends meet.
One day, as I was watching youtube, I decided hey, I could do that, share my story u know, try and inspire people from there. So I did it. In my first video I shared my story and eventually burned my A level cert. You may think its stupid, but its not. That piece of paper almost murdered me, and its worthless to me now, I never want to see it again. The video is long but the first 1hr20mins is the crux. If its too long to tahan, do try and watch it in parts if you can It has 18k views so far and good reviews. After my video, some people with mental illnesses have also come to me for help. It’s tiring helping them, but nonetheless I will never give up, for I was once that person, desperate and yearning for help.
I also made two subsequent videos where I interviews elderly cleaners and gave out masks during the haze periods. I do not understand why in our country when our GDP is one of the highest in the world, elderly cleaners, whose faces are riddled with wrinkles, have to bend over and clean tables.
Also, after I woke up from the nightmare, I begin to see clearly the shortcomings of the education system. It is cruely competitive and places too much emphasis on grades. From a young age, some parents bombard their children with two preschools, piano classes, tuition, sports classes, you name it. Children should be able to enjoy their childhood and slowly find their dreams, not having them forced on them. Because parents want “the best� for their child’s future, they may unknowingly put too much stress on kids from a young age. I remember clearly during my PSLE results, a boy was crying over the phone in the toilet, saying “Mummy, sorry, I got below 200, how?� No child at the age of 12 should feel that their life is over because of a stupid piece of paper.
In secondary schools, many “neighbourhood� school kids are struggling to keep up with the content of the O levels with 6-8 subjects, and face tremendous stress. Some simply give up, and worse still develop mental illness. These claims are not made into jest. For my upcoming videos, I’ve interviewed “neighbourhood school� kids and this is what they tell me. So too do taxi driver uncles (about their sons) whom I talk to.
Of course, when grades are held in high regard, there are other perils and implications on society like elitism and social stratification, which are also serious problems.
Also, though my interactions with my new friends, I realised I was very sheltered, and I finally see the neglected side of society-namely people with disabilities, mental illnesses, learning disabilities and the elderly.
Coming out of depression, I have a clearer dream and conviction; That is to inspire a more inclusive, loving Singapore, where we look out for those falling through the cracks, for those crushed under the weight of a fast paced society, for those who are underprivileged and in need of help. I hope we can achieve that dream together as Singaporeans :)
https://www.facebook.com/kevin.wee.16
Another (unidentified) ex-RJC student subsequently posted this on RJC Confessions Facebook page :
To the Kevin Wee dude who did the video on the education system:
The surest way for one to realise his dreams is to go through the given system that works and aim to be the best. In any society, regardless of what systems there are, there will always be the better and lousier people - that's a fact of life and there's nothing you can do to change that.
You flunked your A levels because you hate the system- you have an extremely defeatist attitude and you're unwilling to work hard. Your mistake was not that you were bad, but you were senseless to not take the guaranteed path RJ or any JC offers you and instead tried challenging and finding fault with the system. You claim that "other alternative less competitive" paths can get you to success to. Well sure, if these methods worked you wouldn't be here making vlogs for a living, see?
Competition and comparison between the better and the poorer people in any country is inevitable. You hate the system because it's competitive, and people who lag or are left behind suffer a horrible fate. But it is only with this system that the top few people even work hard in the first place. If we didn't have to compete or work hard for our success, then nobody would study hard at all.
It is people like you who kill the determination and driving force in Singapore. It doesn't help that the "lousier" people as we call it are lagging behind, but people like you have to exacerbate things by telling them that JC is hard, PW stress is crazy and whatnot. Yes it is stressful, but are you telling me this stress is necessarily bad? Will you not face stress and failure in your career in future? Clearly, no pain no gain. If you're unwilling to put in 1000%, you'll never make it big. Maybe that's why you're into making vlogs now eh?
And WHAT THE FUCK stop hitting on your juniors by asking them if they're cute, that's just creepy. I have already notified relevant authorities too, have fun.
https://www.facebook.com/RJConfessions/posts/228031204011708
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If you (as a JC student) found RJC Kevin Wee's personal story inspiring or at least helpful to you in some way, you might also be interested in hearing HCJC Xin Lin's story as well. She too, was stressed out by the life as a student in an elite JC, but in case you're wondering, she didn't burn her A level certificate.
Truth behind my JC life :
https://stopthe-pretence.blogspot.sg/2012/03/truth-behind-my-jc-life.html
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Seriously, no takers for my challenge?
To elaborate, barring any silly mathematical errors, there are only 3 possible answers commonly given, depending on your level of Chemistry conceptual understanding : the U grade answer, the D grade answer, and the A grade answer. Based on your answer, I'll assign you your grade.
A BedokFunland JC H2 Chemistry Challenge
99% of Singapore JC students will get this wrong, and about 50% of private tutors and school teachers will get this wrong.
Calculate the pH of 1.0 x 10^-8 mol/dm3 of HNO3.
Go ahead and calculate it, and if you like, post your final answer here to 3 decimal places (note : don't show your working, coz in case you get it right, don't ruin the fun for others). I'll only state if your final ans is correct or wrong, nothing more nothing less.
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Although the new H2 Chemistry syllabus specifies only a qualitative treatment of the Nernst equation is required, but you can bet your ass that most JCs will set Prelim paper questions on a quantitative treatment of the Nernst equation, and so will Cambridge, afterall what better way to illustrate a qualitative understanding than to perform calculations quantitatively?
I have an extensive collection of Nernst equation problems ready for my BedokFunland JC students. All other students can go ask their school teacher or private tutor for practice on Nernst equation problems, and/or go Google out such Nernst equation problems on the internet for yourself to practice on. Have fun! :)
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Now that the Mid Yr exams are over, if any of you JC students would like to share with us any particularly sadistic or guai-lan H2 Chem question from your Mid Yr exam, pls feel free to do so here ;Þ
Or, if you disagree with your school teacher on any Mid Yr exam qn, you can ask me for a 2nd opinion here (just like how if a pediatrician gives your toddler a suspicious diagnosis, you might like to consult another specialist for a 2nd opinion).
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[H2 Chemistry] - "Why or how do acid attacks cause disfigurement?"
Such a simple Chemistry question with such an obvious answer, but you'll be surprised most JC students don't know the answer. And if you protest, "But acid attacks are not in the H2 syllabus!", my retort is : if you've truly educated yourself in Chemistry, it means to intelligently apply whatever you've learnt within the syllabus, to novel contexts beyond the syllabus. So yeah, certainly expect to have Cambridge do this for Chemistry as well, coz it would be totally unfair and a bloody shame if H2 Chemistry and/or H2 Physics loses to H2 Biology in this didactic, pedagogical, examinational characteristic :
There will be one or more stimulus materials which may be taken or adapted from a source such as a scientific journal or book which may not necessarily relate directly to the content of the syllabus. Questions may require candidates to explain terms used in the passage, analyse data, justify decisions, perform calculations and draw conclusions based on information in the stimulus material.
Acid attack first aid: What you need to do immediately to help victims
https://sg.yahoo.com/news/acid-attack-first-aid-immediately-131700262.html
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Can i just ask whether the hardest H2 chemistry topic in the syallabus is Ksp(Solubility Product)?Because out of all the chapters that is the only chapter i face quite some problems comprehending whereas for the rest is pretty much simple and easy to understand.
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Originally posted by MapPwner:
Can i just ask whether the hardest H2 chemistry topic in the syallabus is Ksp(Solubility Product)?Because out of all the chapters that is the only chapter i face quite some problems comprehending whereas for the rest is pretty much simple and easy to understand.
Yes indeed, Ksp questions can potentially be the toughest topic.Feel free to ask for help here with specific Ksp questions your JC may give you. Do include the given solution (either type out or take a photo of the qn and upload the image to your social media account to link here), if available. Then ask me exactly what about the question or solution that you don't understand.
If it's a TYS or Prelim paper qn, just specify the paper, eg. RJC 2016 P2 Q3, no need to type out or upload the photo of the qn.
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The AgSCN,AgBr question seems rather mind-blowing and hard to understand but the 1st question for ammonia and ammonium ion question was understandable.
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Originally posted by MapPwner:
The AgSCN,AgBr question seems rather mind-blowing and hard to understand but the 1st question for ammonia and ammonium ion question was understandable.
That's good on both counts. Good that you found the 1st question to be understandable (already making you above average for H2 Chem students, most of whom would struggle with even the 1st question). And good that you found the 2nd question to be mind-blowing, because it means you truly understood it and appreciated its complexity. Most H2 Chem students don't even recognize its complexity or even understand the question. You're doing ok. Keep it up. -
Have another question though,if you have the PJC MYE paper 2016 or 2017,do you feel that the difficulty of this paper is comparable/near to that of A levels?
My school's HOD reprimanded the cohort for this year's dismal performance for MYE as they felt that the standard of the paper they set this year is easier than 2016(I agree a bit but if I did the last year paper I would have probably scored higher).I personally felt that my school paper(with exception of P3 and P1),was slightly below A level standard or almost comparable,whereas P3 and P1 is comparable to A levels.Do you consider scoring 73% total for the chem paper 2017(including P4 prac) as a whole good?
My school results were:
A:31 students B:60 students Cohort size:434 students
MSG:4.2 50th percentile(mean) score:51.11
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Originally posted by MapPwner:
Have another question though,if you have the PJC MYE paper 2016 or 2017,do you feel that the difficulty of this paper is comparable/near to that of A levels?
My school's HOD reprimanded the cohort for this year's dismal performance for MYE as they felt that the standard of the paper they set this year is easier than 2016(I agree a bit but if I did the last year paper I would have probably scored higher).I personally felt that my school paper(with exception of P3 and P1),was slightly below A level standard or almost comparable,whereas P3 and P1 is comparable to A levels.Do you consider scoring 73% total for the chem paper 2017(including P4 prac) as a whole good?
My school results were:
A:31 students B:60 students Cohort size:434 students
MSG:4.2 50th percentile(mean) score:51.11
I don't have MYE papers, only Prelim papers. So I can't comment on your PJC paper or your results for that paper.Your school MYE performance by grades are typical for most JCs, because i) JCs try to do u students a favour by setting tougher papers and marking more strictly compared to A levels, and ii) most JC students are still not adequately prepared for A levels at this stage.
If 73% is your overall score for the upcoming 2017 TYS A level exam, assuming the bell-curve doesn't deviate too significantly from the past few years, you'll have approx 50% chance of scoring A grade (just as you yourself have correctly noted the grade boundaries for H2 Chem, subject to the bell-curve). But most students tend to over-count their own marks, not realizing they've made either careless mistakes, or that Cambridge may penalize them for some of their answers' phrasings (which they blindly memorized from their school lecture notes, which may not be fully acceptable by Cambridge, or which may need to be further adapted to the question at hand).
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Originally posted by UltimaOnline:
I don't have MYE papers, only Prelim papers. So I can't comment on your PJC paper or your results for that paper.Your school MYE performance by grades are typical for most JCs, because i) JCs try to do u students a favour by setting tougher papers and marking more strictly compared to A levels, and ii) most JC students are still not adequately prepared for A levels at this stage.
If 73% is your overall score for the upcoming 2017 TYS A level exam, assuming the bell-curve doesn't deviate too significantly from the past few years, you'll have approx 50% chance of scoring A grade (just as you yourself have correctly noted the grade boundaries for H2 Chem, subject to the bell-curve). But most students tend to over-count their own marks, not realizing they've made either careless mistakes, or that Cambridge may penalize them for some of their answers' phrasings (which they blindly memorized from their school lecture notes, which may not be fully acceptable by Cambridge, or which may need to be further adapted to the question at hand).
Ah I see ok.
I figured if I didn't rush through the paper as I just wanted to finish the paper within time limit and more concerned for my p3(I was reading bio the day before as I was tired of chem),may have done much better due to presence of many errors,whereby eliminating them 80% could even be possible.
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Originally posted by MapPwner:
Ah I see ok.
I figured if I didn't rush through the paper as I just wanted to finish the paper within time limit and more concerned for my p3(I was reading bio the day before as I was tired of chem),may have done much better due to presence of many errors,whereby eliminating them 80% could even be possible.
Overall 80% is ideal and sufficient to safely secure an A grade for H2 Chem, even allowing for a couple of % points overestimated by the over-confident student. Truth be told, after the bell-curve processing, the A grade boundary has never reached 80% for H2 Chemistry, and in most years, a 75% is sufficient for an A grade. The main problem, as I mentioned previously (and many times in previous years), is that over-confident students frequently over-estimate their own marks, eg. assuming Cambridge will mark the same way as their JC teachers. -
Originally posted by UltimaOnline:
Overall 80% is ideal and sufficient to safely secure an A grade for H2 Chem, even allowing for a couple of % points overestimated by the over-confident student. Truth be told, after the bell-curve processing, the A grade boundary has never reached 80% for H2 Chemistry, and in most years, a 75% is sufficient for an A grade. The main problem, as I mentioned previously (and many times in previous years), is that over-confident students frequently over-estimate their own marks, eg. assuming Cambridge will mark the same way as their JC teachers.Yep I know I even tried estimating my scores for individual components before determining my overall %,which i estimated to be 70%.
I estimated P1 to be 24/30,P2 56/75,P3 52/80,P4 30/40.
Got my paper back,it was 19/30 for P1,P2 55/75,P3 58/80,P4:31/40,overall 73%.So my estimation was a bit off for P1 and P3.
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Hi there, I'm revising my A level chem + learning higher level chem to prepare for a chem test so I can exempt from chem mods. I have this question to ask.
Which of the following compounds would react most rapidly with NaCN?
a. 1-bromobutane
b. (R)-2-bromobutane
c. (S)-2-bromobutane
d. 1-bromo-2-methylpropaneMy deduction is that either a or d is the answer, since b and c are technically the same compound (except the direction)
Now, how do I know which will react faster? a has 1 R group, compared to d which has 2 R groups. I feel that d is more stable and so d would react most rapidly with NaCN. Am I right?
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Originally posted by supercat:
Hi there, I'm revising my A level chem + learning higher level chem to prepare for a chem test so I can exempt from chem mods. I have this question to ask.
Which of the following compounds would react most rapidly with NaCN?
a. 1-bromobutane
b. (R)-2-bromobutane
c. (S)-2-bromobutane
d. 1-bromo-2-methylpropaneMy deduction is that either a or d is the answer, since b and c are technically the same compound (except the direction)
Now, how do I know which will react faster? a has 1 R group, compared to d which has 2 R groups. I feel that d is more stable and so d would react most rapidly with NaCN. Am I right?
This is still considered an A level Chem qn, so I'll help you out here. Once you do Uni level Chem proper, you can post your Uni Chem qns at The Chemical Forums, as my professional interest (as Mr BedokFunland JC) is specifically targeted at A level Chem only.Options A and D are both primary alkyl halides (your thinking that Option D is a secondary alkyl halide is incorrect : only if Option D was 2-bromo-2-methylpropane, then it would be tertiary, and 1-bromo-2-methylpropane is still primary), hence the electronics factor is similar. Therefore, the least sterically hindered Option A would be the fastest.
For Options B and C, apart from your correct deduction that optical isomerism is irrelevant to the rate of reaction, let's consider them for the sake of comparison with Options A & D. Even though electronics would favor the secondary alkyl halides Options B & C for SN1 (over primary alkyl halide Options A & D), but the strong NC- nucleophile would favor SN2 anyway. Hence being SN2, Option A is fastest, followed by Option D, with Options B and C the slowest.
If instead of 1-bromo-2-methylpropane, 2-bromo-2-methylpropane was specified for Option D (which was what you were prolly thinking of), then Option D (tertiary) would be faster than B & C (secondary) only if SN1 was favored (ie. weak nucleophile, and preferably protic solvent). Since SN2 is favored (ie. strong nucleophile, preferably aprotic solvent) in this question (although the solvent isn't specified by the question), then if Option D was 2-bromo-2-methylpropane, Option A (primary) would still be the fastest (even moreso than Option D being 1-bromo-2-methylpropane), followed by Options B & C, with Option D the slowest (due to greatest steric hindrance).
Note that we've only considered nucleophilic aliphatic substitution SN1 and SN2 here, rather than elimination E1 and E2 (since solvent and temperature weren't specified by the question). If E1 and E2 are to be considered, a primary alkyl halide in an aprotic solvent with a strong Bronsted-Lowry base such as the NC- anion would favor E2 over E1, while a tertiary alkyl halide in a protic solvent with a weak Bronsted-Lowry base would favor E1 over E2.
