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The Mind-Boggling H2 Chemistry

posted Nov 16, 2016, 8:15 AM by Grace Ong   [ updated Dec 17, 2016, 1:24 AM ]
The following post was first posted on Blogger on Monday, 23 September 2013.



End-of-year examination season is here, and I am facing glum faces looking like this Saint Bernard all around me every day.

sad face of a saint bernard

A common refrain among students these days is that H2 Chemistry is so hard, much harder than their other H2 subjects. While I can't speak for the other subjects, I have to agree with them that H2 Chemistry is HARD.

Chemistry at 'A' Level was never this difficult though, but things seemed to have changed in recent years. I can't exactly pinpoint when this trend began, but it probably coincided with the time Cambridge examiners decided to up the ante for Singapore candidates with an unprecedentedly difficult paper in 2010. From then on, it became a norm for Cambridge to design questions that are set in novel and unfamiliar contexts.

A case in point: candidates were usually only required to identify chiral centres in optically active compounds in the past [e.g. 2002-Paper 2-Question 5(a)(iv) and 2010-Paper 3-Question 2(c)(ii)]. In 2012 however, candidates were asked to deduce and describe the three stereoisomers of tartaric acid − two enantiomers and one meso compound (diastereoisomer) [2012-Paper 2-Question 5(c)], the latter of which, I believe, was barely covered by most junior colleges. Not unexpectedly, it was reported that only a minority of candidates answered this well.

To equip students to meet the new demands of the H2 Chemistry paper, Singapore teachers, being the typical kiasu Singapore teachers that we are, went into overdrive to 'toughen up' our charges. The new generation of questions that we design integrates multiple topics and is increasingly set in novel and unfamiliar contexts. Questions, such as following taken from the 2011 Anglo-Chinese Junior College (ACJC) preliminary examination paper, became commonplace.

Compare a Chemical Kinetics question now...

(To access an expandable version, click here to view slides on SlideShare.)

and then, during the good old days of reasonably difficult H2 Chemistry papers.

(To access an expandable version, click here to view slides on SlideShare.)

It's a really, really huge leap from 'O' Level Chemistry, and many students get a rude shock when they face their first major H2 Chemistry assessment in the first year of their 'A' Level course. Except for the most able students, many students find it a herculean task to bridge that gap within one-and-a-half to two years.

The unabated overzealousness of Singapore teachers does not help either. The standard of recent preliminary examination papers has risen so high that it has surpassed that of post-2010 Cambridge papers. In fact, the 2011 ACJC Chemical Kinetics example above is considered to be of average level of difficulty; there are many questions out there which are more mind-boggling than this.

I sometimes wonder if we, as teachers, have gone overboard, perusing pages of research papers and scouring the internet for that next big novel question to stump our students. To get our students used to answering such questions, we make them spend a disproportionate amount of time practising past examination questions. Learning Chemistry has not only become a painful process, it is also becoming demoralising as well.

But Chemistry is an experimental science; it is NOT about answering difficult examination questions. Rather than spending so much time on figuring out solutions to complex questions such as the ones below,

Example of an Organic Synthesis Question
(To access an expandable version, click here to view slides on SlideShare.)

Example of an Organic Structure Elucidation Question
(To access an expandable version, click here to view slides on SlideShare.)

shouldn't time be better spent in the laboratory learning how some of these organic reactions are actually carried out?

Many a time, I wish that the 'A' Level syllabus is taught over three years instead of two. As a teacher, I want to slow things down so that my students can spend more time in the laboratory, read beyond textbooks and more importantly, apply theoretical concepts in a practical setting. I want to use the time to pique the curiosity of my students, evoke their sense of wonder, encourage them to think, question and discover new things for themselves. I don't want them to face one examination paper after another, which at the end of the day, are just papers, not Chemistry.

Alas! The pace never slows down in Singapore, and our obsession for As continues.

Little wonder that we have never produced a Nobel Laureate, or even close to producing one.
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