2018 H2 Chemistry JC students post your questions here

tk2018 SG

Appreciate your candour. Thanks for being honest about your Chem postgrad background.

As you say this is the internet (though from a review of one's postings, one can more or less deduce the truthfulness of one's professed identity, eg. nayr69sg does appear to be a real Singaporean medical doctor who is currently practicing medicine in Canada), but I still routinely ask a new SgForum member's background and current profession (which I noticed you've sidestepped, eg. whether you're currently a Chem private tutor or Chem MOE school teacher, but I'll leave it to you whether you wish to share on this), when I notice unusual posts (eg. if the content of the posts clearly indicate the poster is almost definitely not a JC student, this simple fact can be used to assess the honesty of the person by asking the person's background, and 4/5 times I get the less-than-honest response, "I'm just a neighbourhood JC student lah", ok lor if u say so...), and this (my asking the poster's background), is not so much for measuring dicks, but rather that, if the poster (ie. the person I'm talking to) turns out to not actually be a current JC student (the poster being a JC student is a reasonable initial assumption since this forum is for current JC students to ask me for help), and instead turns out that the poster (ie. any newcomer who responds to my Chem qns or asks me Chem qns) is actually currently an undergrad or post grad or fellow private tutor or MOE school teacher, then it would be wholly inappropriate (rude even) for me to appear condescending and 'talk-down' to the poster (ie. when discussing Chemistry concepts, eg. If I replied you with a "Go google or ask your school teacher on the definition of such-and-such, then get back to me with your revised answer", which would be pedagogically appropriate if you are indeed a JC student, on the other hand would naturally be offensive if you're an undergrad or post grad or fellow private tutor or MOE school teacher, something I'd rather avoid, which is why I ask of the person's background and current profession, and hope to receive an honest response.

Indeed, the 1 out of 5 respondents in past years, a mere handful, did reply me (sometimes through private messaging), to say they are currently an undergrad or post grad or fellow private tutor or MOE school teacher, I appreciated their candour. And it made me all the more willing to help them with their Chem questions, and with more level-appropriate replies, eg. "I'd suggest you advise your students to do it this way...".

All in all, tk2018 (whether you're currently an MOE teacher or private tutor or something else altogether), welcome to SgForums, and you're welcome to join me in advising and helping out Singapore JC students with their questions, although in all honesty, you'll probably be disappointed and bored with this forum, because business is slow (ie. not many JC students ask for help here), despite my sincere hopes that all Singapore JC students who can't afford private tuition, register an SgForums account to receive help with their JC subjects here (other than myself and Chemguide7 for Chemistry, Wee_Ws helps out for Mathematics, Eagle helps out for Physics and Mathematics, and Darkness_hacker99 helps out for Biology, but business (ie. students asking qns) has been so slow in recent years, that these folks only drop occasionally these days, if at all.

tk2018, if you do have your own Chemistry website, or blog, even if it's your own private tuition website, if it contains useful materials for students, not necessarily study notes, can be a collection of links to interesting Chemistry articles etc, feel free to post your url here to share with JC students (from the logged statistics, the vast majority of visitors to this forum are lurkers, and while there are certainly many private tutors and school teachers lurking here, I'll like to think that there are many genuine JC students visiting here as well, and would like to encourage them to register an SgForums account to get help for their A level subjects here, especially if they cannot afford private tuition).

Mr Chong (Chemguide7)'s H2 Chemistry website :
http://www.alevelchemistrysg.com/

My BedokFunland JC website :
http://www.bedokfunlandjc.com/

Thanks UltimaOnline for your kind words. I don't just help with A level Chemistry questions. I am also interested in trying to help students aim to get into the better universities/courses. Managed to get one of my students a university scholarship offer.

UltimaOnline SG

You referring to your MOE school student or your private tuition student (it'll be easier to communicate if we just get this out in the open)?

So you teach / tutor others subjects other than Chemistry? What other subjects do you help out with? And can help out with on this forum?

So how would you help SgForum students "get into the better universities/courses"? You wish to offer your services in advising and counselling students on academic pathways? Here on SgForums, or specifically helping your own school / private tuition students?

No offence with all these questions, just that it would help facilitate clearer communication if we have a better idea of exactly what you're offering or intending to offer, specifically via this forum.

tk2018 SG

1. My private tution student. I do this part time; I have a full time job elsewhere.

2. No, my focus is chemistry.

3. Not offering any paid services via this forum. Prefer to be anonymous for now. What I meant was students can post general questions on how/what to do when it comes to scholarships/universities' applications; if the questions can be answered on the forums.

UltimaOnline SG

1. My private tution student. I do this part time; I have a full time job elsewhere.

2. No, my focus is chemistry.

Understood, thanks for your reply and sharing, appreciate it.

"Students can post general questions on how/what to do when it comes to scholarships/universities' applications; if the questions can be answered on the forums."

Thanks in advance for your willingness to help out students with their questions on their further education. I hope many JC students will take up your kind offer, register an SgForums account and post their further education queries here.

UltimaOnline SG

The following MCQ is a Cambridge A level MCQ, used in both the UK and Singapore papers.

When iron reacts with aqueous iron(III) ions, iron(II) ions are formed as the only product. A final mixture, after the reaction has taken place, contains equal numbers of moles of Fe2+(aq) and Fe3+(aq). Assuming the reaction has gone to completion, how many moles of Fe(s) and Fe3+(aq) were in the starting mixture?

I remember coming across a Singapore JC Prelim / Tutorial MCQ which used this MCQ and gave it a twist to make it tougher. I searched for it but can't find it. If anyone recognizes the Singapore JC Prelim / Tutorial MCQ I'm referring to, please post the JC and year, or the MCQ itself, thanks.

UltimaOnline SG

The following MCQ is a Cambridge A level MCQ, used in both the UK and Singapore papers.

The modified Prelim / Tutorial MCQ could be that the final amount of Fe2+(aq) and Fe3+(aq) were in the molar ratio of 2:1 or 1:2 (or any ratio you like), instead of 1:1. But such a slightly modified MCQ would still be considered easy (to be honest).

I seem to recall the modified Prelim / Tutorial MCQ being a tad more interesting (students would say 'sadistic') than this, but a pity I forget the exact modification. Anyone recognizes the modified Prelim / Tutorial MCQ I'm referring to, please share it here, thanks.

UltimaOnline SG

Came across this in a 2017 Singapore JC Prelim Paper, which shall remain unnamed.

Marker’s comment : There are still some students who drew mechanism like A --> B --> C --> D, the correct way to draw is A --> B, B --> C, C --> D.

No, that is just totally wrong. Although Cambridge will accept either way for A level purposes, the correct (ie. University) way, and indeed the way preferred by Cambridge markers at A levels, is to draw A --> B --> C --> D.

To draw A --> B, B --> C, C --> D is a terribly inefficient and childish way, which Cambridge tolerates but discourages, even at A levels.

Here's an example of how we draw mechanisms at University levels, and thus also the recommended way for competent (not childish) A level students :

https://en.wikipedia.org/wiki/Benzoin_condensation

UltimaOnline SG

[Singapore] - A young woman scholar from the Agency for Science, Technology and Research (A*Star) was suspected to have taken her own life at a laboratory early Tuesday (Jan 16 2018) morning. Colleagues of Katarina Chlebikova, working at the Institute of Molecular and Cell Biology (IMCB), said that the 26-year-old Slovakian had been troubled over work and relationship issues before her death. In response to media queries, the police said that they were alerted to the case at 10.44am on Tuesday. Her body was found on the eighth storey of 61 Biopolis Drive, where the institute is located. “A 26-year-old woman was found motionless and was pronounced dead by paramedics at scene. Police are investigating the unnatural death,” they added. TODAY understands that Chlebikova left behind a note suggesting that she killed herself via nitrogen poisoning.

http://www.todayonline.com/singapore/astar-scholar-found-dead-lab

BedokFunland JC's comments on the chemistry involved :

Nitrogen gas itself is physiologically inert and non-toxic, unlike carbon monoxide. However, deliberately pumping into a room excess nitrogen gas, displaces all other gases from the room, including oxygen. This results in asphyxiation and death from oxygen deprivation, as would occur with carbon monoxide poisoning.

That this method can be used, and has been used, to carry out covert assassinations, is known to agents of intelligence agencies such as the CIA, Mossad, MI6, KGB, etc. In the case of the 26-year-old Slovakian young woman in Singapore, she used this method for committing suicide.

Spiritually and karmically, the state of emotional and psychological distress that drove her to commit suicide, will accompany her into the afterlife, and will pose some difficulty in releasing her consciousness from her post-mortem emotional pain and psychosis, and she may need some time to herself before willing to accept and experience love and forgiveness, for sufficient healing of her psychological trauma to occur, before she can move forward vibrationally, onto the intermissive period proper, where further healing, life review and preparation for her next physical incarnation can occur. She will be supported by her guides & helpers at every step of the way, even if she may not be aware of it through her emotional pain. Rest in peace now, Miss Katarina Chlebikova.

Photo : https://sg.news.yahoo.com/duke-nus-medical-school-student-found-dead-biopolis-laboratory-051706805.html

UltimaOnline SG

[Chemistry / Medicine / Biology] - YouTube account 'Chubbyemu', a medical doctor, did an 're-enactment' video on the medical tragedy of chemist Karen Wetterhahn

https://www.youtube.com/watch?v=NJ7M01jV058

https://en.wikipedia.org/wiki/Karen_Wetterhahn

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