Hi Students (and Parents),

With GCE ‘O’ Level Examinations coming in less than 5 months time, how many of you are prepared for it?

Not sure? Take a look at your Mid-Year Examination Paper + Sec 3 End-of Year Paper + Continual Assessment Tests recently.  If you are not scoring B3 and above, it might shows that you are not that ready for ‘O’ Level Examinations.

Click HERE for Early Bird Price registration!

Some would argue that you do not have enough time to revise and memorise all the materials before you have gone for your Mid-Year Exams, and thus the not-so-good results you are getting.

But is that true??????

Now, Chemistry is a abstract subject of Science (as compared to Physics and Biology) and you need good understanding of the essential concepts in order to score. Only about 10% of the marks are awarded based on recalling of facts (i.e. memorising itself might help here), with the rest (90%) all based on your understanding and application to challenging questions.

More importantly, ALL the Chemistry Topics are inter-related and it is the norm this days that a structured chemistry question is based on 3-4 topics. As such, it is of paramount importance to have a strong foundation of essential concepts in all the chemistry topics! SORRY you cannot skip topics and expect to do well in Chemistry!

Every June Holidays, we have groups of students that came to our June Holidays Intensive Revision Bootcamp to master their Chemistry concepts. These students realised that June is perhaps the last chance for them to really master Chemistry – and they continue to do well for the ‘O’ Level Examinations in 5 months time

[98% of our 2009 batch scored 'A's or 'B's from 'D' - 'F' grade]

[97% of them achieved minimum 3 grades jump]

This June Holidays, i will be personally coaching you on the following key essential chemistry topics: (more…)

(Geodesic Domes @ Eden Project in Cornwall. Photo Credit)

In Chemical Bonding chapter of Basic Chemistry Syllabus (O Levels, etc), you have learned about the term Allotropes as well as Macromolecules.

To be more exact, you learned that Allotropes = Compounds with the same element with different structure.

The two examples you learned are Diamond and Graphite, which are Allotropes of Carbon.

Now, i would like to introduce to you another allotrope of carbon that have found so many applications into our daily modern lives. Think of Apple, iPod, iPad, Macbook, iPad, Blackberry, Nokie, smaller and thinner electronics consumable products.

This is FULLERENE. C6o – highly symmetrical spherical football-shaped molecule – which was obtained by firing a powerful laser at a sample of graphite at a temperature of 10, 000 degree Celsius. It was named as Buckminsterfullerene in honour of the architect R. Buckminster Fuller, who used to be the principle of the geodosic dome in many of his buildings.

Molecular Model of C60, Fullerene (Photo credit St Stev)

Look at the molecular structure and you will realised that the alternating 5- and 6-membered rings in C60 gives a bonding pattern similar to the struts in a geodosic dome.

In fact, from the point C60 was found and honoured, other fullerenes such as C70, C76, C78, C90, etc has been synthesized and i expect many more to be synthesize to open up more exciting new areas of Chemistry and its application in the modern world.

As stated earlier on, fullerenes found its many application in the semi-conductors industry.

Now, time for you to put on your thinking caps:

Question:

Is fullerene a good or non-conductor of electricity? Explain with reference to its structure and bonding properties.

(Clue: Refer to structure and bondings in Graphite (Good Conductor) and Diamond (Non-Conductor))

PS: I would love to hear from you. Think about it and leave your comments below. It is actually very easy. =)

(Photo credit Ingy The Wingy)

Besides sharing Chemistry Tips and Exam Strategies, the other aim of this chemistry blogsite is to encourage students to learn the Chemistry Theories and Concepts in a more experiential and interesting way – HOW ? By relating chemistry theories to everyday life processes and experience.

Thermit Process came to my mind several days back when i was passing by the railway track in the west area of Singapore, and today i am going to share with you more on how Thermit Process – which is a highly exothermic reaction is used to weld together steel railway lines. It involves the reduction of iron (III) oxide to iron by aluminium.

Now, let’s check out a chemistry question that requires your concepts in several chemistry topics, namely:

• Energy Changes (Endothermic/Exothermic Reactions)
• Redox (Oxidation/Reduction)
• Mole Calculations

Question:

In the highly exothermic Thermit Process to weld railway lines, aluminium is used to reduce iron (III) oxide to iron based on the balanced chemical equation below:

2Al   +   Fe2O3   ->   Al2O3   +   2Fe

(a) Indicate the state symbols for all the reactants and products involved

(b) Calculate what mass of aluminium is needed to react completely with (more…)

Recently, i received several emails and comments from readers (students) to share more challenging Mole Calculations (or Mole Concepts) questions in this chemistry blog.  So here we go………..

Question:

What would be the concentration of the hydrochloric acid produced if all the hydrogen chloride gas from the reaction between 50g of pure sulfuric acid and an excess of sodium chloride was collected in water, and the solution made up to a volume of 400 cm3 of water?

Based on equation: NaCl(s)   +   H2SO4(aq)    –>   NaHSO4(s)   +   HCl(g)

Now, try it out and leave your suggested answer (and possibly your solution/steps) in the comment section below.

The best way to learn is NOT by reading or looking, instead it is by Taking Actions.

I look forward to seeing you answers. Cheers! Enjoy! =)

(Photo Credit: pet-rubber-duck)

Books, Books, Books! They are something we cannot do without – be it in leisure (novels, magazines, etc), academic (school textbooks, revision books, workbooks, etc) or self-improvement (motivation, self-development, etc).

Even with the advance of technology, the kindle, the ipad, the macbook, the netbook, etc – we all still need and want books.

In fact there is a group of people that simply love old books. They love the smell, feel and look (usually torn and with dark brown patches) of these old books – usually fragile and tattered.

Now, what causes the book to turn brown, black and fragile? We need to studyinto the manufacturing of papers before they are imprinted with words and binded into books.

Chemistry Concepts behind the Fragile Looks of Old Books:

During paper manufacturing, the chemical Aluminium Sulfate is often used to treat the papers, before they are imprinted with words and binded into books.

Over time, the aluminium ions (due to dissociation from aluminium sulfate) in the paper will react with moisture in the air to produce Hydrogen Ions (H+).

These hydrogen ions break down the Cellulose in the paper (paper is organic in nature and made of cellulose) and make the paper brittle. This is the reason why the pages in old books become very fragile after long use.

Now, can we do something to slow down the rate of the papers of old books becoming fragile? ie, can we slow down the rate of reaction – can we slow down the rate of formation of (more…)

I was surfing the Youtube and came across a youtube video that i had produced sometime in Oct 2008.

It is a pleasant surprise that the video has over 36,000 views after a short one-and-a-half year. Saw many encouraging and interesting comments also.

Set A: COCA-COLA ZERO + MENTOS MINTS
vs.
Set B: PEPSI MAX + MENTOS MINTS

You can check out via the youtube link HERE

As in all chemistry experiment, we have tried to keep all parameters/conditions the same (if not similar):
1. Surrounding Temperature the same
2. Surrounding Pressure the same
3. Volume is the same (both are 1.5L by volume)
4. Equal amount of Mentos Mints were added

PS: Let me know how you feel about this experiment. I would love to hear from you.

PS: Another experiment (failed) also has over 10,000 views.  Check it out HERE.

(Photo Credit: Elsie esq)

Combustion reactions are only one means of extracting useful energy from fuels. Over the years, scientists all over ther world have explored the possibility of converting the chemical energy of fuels directly to electricity.

They call this new possibility as “Fuel Cell” – A chemical cell in which reactants (usually a fuel and oxygen) are continuously supplied to produce electricity directly.

The most common type of fuel cell is the Hydrogen-Oxygen Fuel Cell which is used as a source of electrical power in many spaceships and vehicles.

A Hydrogen-Oxygen Fuel Cell is indeed a Chemical Cell and consists of 2 electrodes – a positive electrode (Cathode) and a negative electrode (Anode).

At the Cathode:            O₂(g) + 2H₂O(l) + 4e^- –> 4OH^-(aq)

At the Anode:                2H₂(g) + 4OH^-(aq)  –>  4H₂O(l) + 4e^-

Overall reaction:           O₂(g) + 2H₂(g)  –>  2H₂O(l)

As you can see from the overall reaction, it involves the conversion of (more…)