Category Archives: Chemistry Phenomenon

Chemistry Phenomenon: Nitrogen Dioxide as an Air Pollutant

Being a Chemistry Trainer and also a fellow cyclists (yes guys, i love to cycle), i read this local Straits Times Newspaper article with interest.

Seems like our Nitrogen Dioxide, NO2(g) level within the lower atmosphere level is quite high in Singapore.

NO2(g) is considered a major air pollutant which has the following harmful effects:

1) eye and lungs irritation and causes breathing difficulties

At high levels, it may even lead to inflammation of the lungs i.e. bronchitis

2) acid rain consisting of Nitric Acid HNO3 that is highly corrosive

In the presence of oxygen in the air, nitrogen dioxide is converted to nitric acid via the following chemical equation:

4NO2(g) + 2H2O(l) + O2(g)  4HNO3(aq)

Nitric acid corrodes buildings and harms aquatic life and plants.

Do you know that due to acid rain, the Statue of Liberty in the United States of America had been badly corroded. In the year of 1983, the US Government launched a campaign to restore this historical figure of US? Chemistry in action indeed!

NO2(g) is formed due to 2 main sources:

1) Lightning activities (which we have no control over since it is a natural source and it is NOT a daily source)

2) Vehicle exhaust fumes where high temperature around vehicles engine (which is a man-made source) causes 21% O2(g) and 78% N2(g) in the air to react to form oxides of nitrogen, NOx(g) which is mainly nitrogen monoxide, NO(g) and nitrogen dioxide, NO2(g).

Nitrogen reacts with oxygen at high temperature to form nitrogen monoxide or nitric oxide, NO(g).

N2(g) + O2(g)  2NO(g)

Nitrogen monoxide reacts with oxygen to form a brown colour gas called nitrogen dioxide, NO2(g).

2NO(g) + O2(g)  2NO2(g)

From the article, it shows that as concentration of air particulates (unburnt hydrocarbons) increases due to incomplete combustion of fossil fuels in vehicle exhaust fumes, there is also an increase in the concentration of nitrogen dioxide, NO2(g).

Since the satellites images have shown that the recent haze in Singapore is not from Indonesian fires (slash and burn method), it should be from the amounts of vehicle exhaust fumes produced locally on a daily basis.

  • More vehicles running on the roads
  • More incomplete combustion of fossil fuels
  • More unburnt hydrocarbons being produced
  • More nitrogen dioxide is also being produced
  • As such, the amount of unburnt hydrocarbons and the amount of nitrogen dioxides are highly correlated in a city which has a large number of vehicles running on the ground.

Time to ponder about if Singapore should encourage less driving….for our health and environment.

This is a good case study for GCE O-Level Pure Chemistry and Combine Science Chemistry students in Singapore to put their concepts learned in school into actual practice and application.

Same applies to Chemistry students worldwide doing other syllabus. This can be particularly severe in large cities, where traffic is heavy.

I hope you find the content easy for your understanding and if you have any questions, leave me a comment below.

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Chemistry Phenomenon: Methane, an Air Pollutant is Flammable

O-Level Chemistry Tuition Class - Methane

Source: Yahoo Singapore News on 28th Jan 2014

KABOOM! Yes, methane is highly flammable!

Balanced Chemical Equation for combustion: CH4(g) + 2O2(g) –> CO2(g) + H2O(g)

Besides that, methane, CH4 is also listed as one of the air pollutants (other common pollutants are: carbon monoxide, sulfur dioxide, oxides of nitrogen, unburnt hydrocarbons and ozone) in our atmosphere.

It is colourless and odourless gas, which is produced when plant and animal matter decay.

Sheep and cows give off methane due to the digestion of food so we will have high concentration of this gas in farming areas.

Methane is also produced from the decay of rubbish in landfills.

Scientists are studying closely the concentration level of methane in our atmosphere because it is a potent greenhouse gas which causes global warming and their levels has doubled over the last 150 years because of human activities like fossil fuel use and intensive farming.

The possible consequences of global warming are:

  • Unusual weather conditions such as warm spells, droughts, unexpected storms, floods and tsunamis
  • A decrease in world-wide crop yields
  • Melting of large quantities of ice in north and south poles which will cause sea levels to rise and flood low-lying countries such as Netherlands and Singapore


Air pollution is tested in the GCE O-Level Chemistry Examination in Singapore and is very common. You can find out more information from the two recommended textbooks in Singapore, namely: Marshall Cavendish Education’s Chemistry Matters and Pearson’s All About Chemistry. Refer to the topic called Atmosphere or Air.

Hope you find the above useful and informative.

PS: Feel free to share it with your friends. Keep Sharing; Keep Learning!


Chemistry Phenomenon: Educational Trip to Northern Vietnam – Nov 2010

Youtube video:

Hello everyone!

I reckoned some of you would have finished your major exams (GCE O-Levels, IP, IB and IGCSE). Congrats! It’s time for your to enjoy your holiday before you embark on the next stage of your academic and knowledge pursuance.

It has been a while since you last hear from me. We (Winners Education Group) just came back from our educational trip to Northern Vietnam (Hanoi City, Sapa and Halong Bay, etc) and we have learned alot about their:

  • Educational system for Primary, Secondary, High School and Universities
  • Educational levels as compared to other developed and developing nations
  • History and Literature
  • Language and Economy

And, of course – i saw several interesting Chemistry Phenomenon – Chemistry reactions and actions that are related to our everyday life!

Halong Bay – an UNESCO World Heritage Site has 2000+ limestone structures that are formed due to the wave and wind erosion of one huge island, over thousands and thousands of years.

Halong Bay - Unesco World Heritage

We also saw villagers selling home-made Corn Wine along the streets! This corn wine has 50% v/v alcohol (ethanol) content!

Tribal Lady selling Corn Wine

And apparently some villagers used it to power and run their cars and motorbikes! Chemistry students! Ready for actions? Continue Reading