2011-11-25

Aspartme


I guess many of us have seen this at the coffee shop.  It is an artificial sweeter which is 200 times sweeter than normal sugar we are taking.  Normally it is taken by people with diabetes. 



As we check at its ingredients, it consists of  phenylalanine. The labels "Phenylketonurics: Contains Phenylalanine" is necessary in any food consists of aspartame.  It must be avoided by people with phenylketonuria, a  genetic disorder in which the body lacks the enzyme necessary to metabolize phenylalanine. If not treated, the disorder can cause brain damage and progressive mental retardation. 


Molecular structure of aspartme

2011-11-12

Biodegradable Oil Palm Waste Product



Being creative! Oil palm waste is turned to an useful paper product. Many types of brown cover notebooks on the shelves are biodegradable paper products. Not to surprised the product was invented in Malaysia.

More details, please read http://www.mysinchew.com/node/58773

2011-11-08

Writing an Inference for Reaction involving Alkali Metal


Quick tip when giving inference. Ask yourself WHAT, HOW, WHY.

How does this solution formed?  White powder reacts with//dissolve in water.
Why does this solution turns red litmus paper to blue? The solution is alkaline.
What is that solution? It is potassium hydroxide.


Inference: Potassium oxide reacts with water produce potassium hydroxide which is an alkaline solution



2011-10-30

STAR Exam Seminar on Deepavali


It was Deepavali. But 142 Sekolah Tuanku Abdul Rahman boys gathered in their school from 10.30 am - 1.00 pm to learn study skills for this coming Chemistry SPM 2011. They have shown great interest & took part actively throughout the workshop! All the best to all STAR boys!

2011-10-18

Examples of Redox Reaction

  1. Combustion of metal in oxygen
  2. Reaction between metal oxide and carbon
  3. Reaction between metal oxide and hydrogen
  4. Conversion of Fe2+ ion to Fe3+ and vice versa
  5. Displacement of metal from their salt solution
  6. Displacement of halogen
  7. Transfer of electron at a distance
  8. Rusting of iron
  9. Electrolysis of aqueous solution & molten compound
  10. Chemical cells
Tips : Students should be able to identify
  1. oxidized substance and reduced substance
  2. oxidizing agent and reducing agent all all those reactions
   and explain in terms of
  1. gain/loss of electrons
  2. change in oxidation number
Besides, the skill of writing chemical equation, half equation and overall ionic equation is too very very important.

2011-10-04

Question Analysis for Paper 3 Trial Chemistry 2011 from Different States

Question Analysis for Paper 3 Trial Chemistry 2011 from Different States
View more documents from sweemoi khor

The analysis will be updated from time to time. chem2u welcomes visitor from Penang, Selangor, Wilayah Persekutuan Kuala Lumpur, Kelantan to update the questions in their trials.

Trial Chemistry SPM 2011 from Different State

Thanks to Mr Ch'ng for his effort in collecting exam papers from different states. I believe he will update from time to time.

So far questions from the following states are uploaded:

SBP 2011: Paper1_Paper2_Paper3_Answer
Kedah 2011: Paper1_Paper2_Paper3_Answer
Terengganu 2011: Paper1_Paper2_Paper3_Answer
Negeri Sembilan 2011: Paper1_Paper2_Paper3_Answer
Johor 2011: Paper1_Paper2_Paper3_Answer
Perak 2011: Paper1_Paper2_Paper3_Answer
Melaka 2011: Paper1_Paper2_Paper3_Answer
Sarawak 2011: Paper1_Paper2_Paper3_Answer
Pahang 2011Paper1_Paper2_Paper3_Answer 
Perlis 2011Paper1_Paper2_Paper3_Answer 
Kelantan 2011Paper1_Paper2_Paper3_Answer 
Penang 2011Paper1_Paper2_Paper3_Answer 

2011-10-02

Nalanda Buddhist Society: 1 October 2011 - SPM Examination Workshop - Chemis...

Nalanda Buddhist Society: 1 October 2011 - SPM Examination Workshop - Chemis...:  SPM Chemistry Examination Workshop conducted by Ms Khor Swee Moi.  Student participants were fully captivated by the insightful sharing of the speaker.



2011-09-03

My Periodic Table of Elements


Periodic Table of Elements is essential for students who studying chemistry. It’s just like a map for a traveller.   However, students have their own presentation for their own copy of Periodic Table of Elements.




My Atomic Structure

After studying proton number, nucleon number, electron arrangment in the classroom in Chapter 2, Form 4 students are asked to construct models to show the  atomic structure for different elements.

2011-09-02

Self Inflate Ballon through Reaction involving Acids

The self inflate ballon attracts small kids' attention during K2M 2011
How?
  1. Add 1 table spoon of baking powder to a ballon with a funnel.
  2. Fill a bottle with halfull of vinegar.
  3. Attach the ballon with the baking powder to the bottle.
  4. Quickly por baking powder from ballon the bottle.
Why?

When the baking powder(sodium bicarbonate) is mixed with vinegar(ethanoic acid), the reaction produce carbon dioxide, water and salt.  The production of carbon dioxide gas inflate the ballon

2011-09-01

Sublimation of Dry Ice

Dry ice is the common name for the solid form of carbon dioxide.
It undergoes sublimation at room temperature. 

Uses of Dry Ice:
  • keep ice cream frozen
  • as a refregerants in pharmaceutical, blood and organ shipment

When dry ice sublimates in the glove, the carbon dioxide gas released filled up the glove.

My students during K2M 2011 at National Science Centre

2011-08-14

Coagulation of Latex

Latex coagulates when acid is added.

Latex coagulates when ethanoic acid is added to it. Explain.
  1. Latex is a mixture of rubber particles and water. Rubber particle is made up of  a protein membrane that surrounds many rubber molecules.
  2. The negatively charged protein membrane prevent repel each other. Latex does not coagulate.
  3. Acid which consists of H+ ion is added into the latex.
  4. The H+ ion from acids neutralize the negatively charged protein membrane.
  5. The rubber particles collide with each other.
  6. Protein membrane of the rubber particle breaks. 
  7. Rubber molecules clump together. Latex coagulates.
When latex is exposed to the air for some time, it still coagulates. Why?

  1. Bacteria from the air enter the latex.
  2. The growth of bacteria produces lactic acid.
  3. Lactic acid causes coagulation of latex. But this process occurs slowly. Why?
  4. Slow bacteria action.
How to prevent coagulation of latex? Explain.
  1. By adding ammonia solution.
  2. Ammonia solution consists of OH- ion that neutralize the acid produced by the bacteria.
  3. The rubber particles remain negatively charged.
  4. Coagulation of latex is prevented.
5H students are studying coagulation of latex by adding ethanoic acid

Ethanoic acid is added drop by drop into latex in the beaker. The latex is stirred by using glass rod.


2011-08-12

Different type of Voltaic Cells


Please find more details about the chemicals used for negative terminal, positive terminal & electrolyte and its advantages/disadvantages.

2011-08-11

Simple Voltaic Cell



Explain the production of electricity in the simple voltaic cell.

  1. Magnesium is more electropositive than copper.  Magnesium is the negative terminal.
  2. Each magnesium atom donates two electrons to form a magnesium ion.  Mg --> Mg2+ + 2e-
  3. The flow of electrons from the magnesium ribbon to the copper through the external circuit results in the production of electricity.
  4. The hydrogen ions from the electrolyte(sodium chloride solution) are discharged at the copper plate by accepting electrons to form hydrogen gas.  2H+  + 2e- --> H2
What is the observation at each of the terminal? 

Please respond by leaving your answer in the comment box.

2011-08-03

Heat of Neutralization and the Strength of Acids and Alkalis

  1. Heat of neutralization between a strong acid and a strong alkali is always -57.3 kJ mol-1.  Why?
Heat of neutralisation is the sum of of energy absorbed during bond breaking in the acid and alkali and energy released during bond formation of water molecule from H+ ion and OH- ion.  All the reactions form 1 mole of water. 


2.  Heat of neutralization for neutralization involving weak acid or weak alkali is less than -57.3 kJ mol-1.  Why?
Weak acid/akali does not ionises completely in water. Some energy released during formation of water is used to ionises the weak alkali/acid.



    2011-08-02

    Heat of Neutralisation

    Definition :

    Energy change when one mole of water is formed from the neutralization between one mole of hydrogen ion from an acid and one mole of hydroxide ions from an alkali.
      
    5H students are carrying out experiment to determine heat of neutralisation between an acid with an alkali.





    2011-07-29

    Sharing Scientific Skills with SMK Puchong Jaya

    It was my pleasure to have this opportunity to meet students from SMK Puchong Jaya.  We had a great sssion to learn and practise scientific skills evaluated in Paper 3 Chemistry SPM.


    All the best to all Chemistry SPM candidates from SMK Puchong Jaya.

    2011-07-24

    Polypropylene in Daily Life

    Polypropylene as fabric
    • The first polypropylene was produced by Professor Giulio Natta in 1954.
    • It was later widely used  as injection moulding applications(Example: packaging, parts for electronic and electrical appliances, caps and closures, toys, luggage and a variety of household goods)
    • Second largest use iof polypropylene is n fibres sector. (Example: thermal underwear & storage box)
    • Film & sheet market: uses in the pacckaging of sweets, snack foods and cigarettes.
    • The structure of polypropylene(polypropene)


    For more info, visit
    

    2011-07-21

    Kuiz Kimia Kebangsaan Malaysia 2011



    86 students from my school were taking K3M 2011 this year. Hopefully more students will be awarded Sijil Merit, Sijil Kepujian & Sijil Cemerlang.

    Pocket Warmer



    This pocket warmer use chemicals that react to release heat.  The heat given off through exothermic reaction can be used to warm up body.  Mountain climbers bring pocket warmer  when they are high in the mountain. It can be used to lessen the pain of aching muscles.

    2011-05-30

    Chemistry Form 5 Mid Year Exam SBP 2011

    Please click here to download the Paper 1, 2, 3 & answer scheme.

    This exam covers all topic in Form 4 and chapter 1 & 2 in Form 5.

    A good tools to review how much you are ready for SPM.

    2011-05-09

    Numerical Problems Involving the Factors that Affect the Rate of Reaction

    Numerical Problems Involving the Factors That Affects the Rate of Reaction

    2011-05-05

    Revision Guide for Carbon Compounds

    Carbon Compound Ver Diagram

    2011-04-24

    Electrolysis of Copper(II) Chloride


    The usage of cartoon in explaining the concept of electrolysis copper(II) chloride solution. Another alternative for students to understanding an abstract concept in chemistry.

    2011-04-09

    Esterification Reaction

    Esterification occurs between carboxylic acids and alcohols.

    The colourfull notes from my students(5H) show reaction between ethanoic acid and different alcohols(methanol, ethanol, propanol and butanol).



    2011-04-08

    Isomers of butene

    Isomers of butene


    Isomerism occurs in alkene due to
    1. branching
    2. position of carbon-carbon double bond
    Photos show possible isomers for butene, C4H8.  Can you draw their strutural formulae and name them?

    Their names are as follows:

    Top: but-1-ene
    Left: 2-methylprop-1-ene
    Right: but-2-ene

    2011-04-07

    Carboxylic Acids




    General formula of Carboxylic acids: CnH2n+1COOH, n = 0, 1, 2.....
    All the carboxylic acids have the same functional group, which is carboxyl group, -CO

    Can you write molecular formulae and draw structural formulae for the molecules in the album above?


    Feel free to drop your answers in the comment box.

    2011-04-01

    Science & Technology Week 2011

    Date: 11- 15 April 2011
    In commerating International Year of Chemistry 2011, school has planned a series of activies as follows:

    1. Essay Writing Competition(EWC)

        Theme: Chemistry – Our Life, Our Future
         *limited to 3000 words only.  For more details, click here.
     
    Open to all students. Essay of the winners will  be submitted by the Principal of the school for the National level EWC.  Grand prize is waiting as the first prize winner in the national level will be fully sponsored to attend the closing ceremony of International Year of Chemistry in Brussels, Belgium from 1 - 3 Dec 2011.

    2. Atomic Structure Design

        Use your own imagination and contruct your own 3D atomic model. You're free to use any materials.

    3. My Periodic Table!

        What is your own version of Periodic Table of Element! Prepare one and share with us. The creative one will be the winner!

    4. Chemistry Quiz

        Date: 11 April 2011
        Topic: Numerical Problems relating the concept of moles, chemical equation & concentration.
        4 students will be chosen randomly from each form 5 on the day of event to take part of the quiz. The more question you answer correctly, the nearer you are to the grand prize!

    5. Karnival Kimia Malaysia(K2M) 2011

        Date: 15 April 2011
       A bus of 40 students from our school will attend K2M which will be held in National Science Centre.  A series of activities is waiting us : poster exhibition, demonstration and hands-on experiments, slide and video shows, talks & lectures on the theme and sub-themes, quiz and competition, etc.

    2011-03-10

    Karnival Kimia 2011(K2M 2011)



    In conjunction with International Year of Chemistry 2011(IYC), Malaysian Institute of Chemistry will organize a series of activity to promote awareness of public towards the importance of chemistry.

    Event planned for students are
    1. Karnival Kimia 2011(K2M 2011) which will be launched on 15 April 2011 at National Science Centre.
    2. IYC Essay Writing Competitition for Upper Secondary School Students.
    I wish all students especially SESERI students involve actively in the above activities.

    For more details, please visit Malaysian Institute of Chemistry official website.

    2011-03-08

    Kuiz Kimia Kebangsaan Malaysia(K3M) 2011 Open for Registration


    Date : 21 July 2011(Thurday)
    Time : 10.00 am.
    Registration fee: RM10

    Students who perform excellent in this quiz will be shortlisted for getting ready for International Chemistry Olympiad(IChO). For more details, click here.

    Any students who are interested, please register with your chemistry teacher.  Closing date is 27 May 2011

    2011-03-07

    IYC Global Stamp Competition


    Who can take part?
    Students all over the world(12-14, 15-18, undergraduates/teacher students)

    Aim
    design a national stamp that reflects on 'Chemistry as a Cultural Enterprise', showing the chemical impact on
    the culture and/or every day life in your country.

    Start of the Competition
    29 Jan 2011

    End of the Competition
    15 June 2011

    Winning Design will be on show during the IYC 2011 Closing Ceremony in Belgium on 1 Dec 2011.

    For more details, click here.

    2011-03-03

    Dilution method formula


    Many students always get confused when using the dilution method formula especially when susbstituting value for V1.

    For the above situation, we shall substitute the value as follows.

    M1V1 = M2V2
    2V1 = 0.2(100)
    V1= 10 cm3

    From the calculation, we know that
    1. 10 cm3 of is pipetted from 2.0 mol dm-3 sodium hydroxide solutoin and transferred into a volumetric flask.
    2. 90 cm3 of distilled water is added into the volumetric flask. The volumetric flask is shaken well.
    3. 100 cm3 of 0.2 mol dm-3 sodium hydroxide solution is ready.

    2011-03-01

    Atomic Structure of Sodium Atom


    How to describe atomic structure of sodium atom?
    • Proton number of sodium is 11.
    • Nucleon number of sodium is 23.
    • Sodium atom has 12 neutrons.
    • Sodium atom has 11 protons.
    • Protons and neutrons are found in the nucleus of the sodium atom.
    • Sodium atom has 11 electrons. The electrons are moving around the nucleus in their shells.
    • Electron arrangement of sodium atom is 2.8.1.
    • Sodium atom has 1 valence electrons.
    Similar questions was found in SPM 2006 & SPM 2007. For more details, click here.

    2011-02-15

    Chem Quest 2011

    Mr Adura has compiled a set of multiple choice questions from SPM and trial papers from 2003 - 2009 according to chapter. It's helpful for every students to attempt this question after a chapter is taught in the class. Students will have better understanding to apply their chemistry concepts in different situation. To download the question,

    Form 4

    Form 5













    Chapter 8
    Chapter 9

    Thanks Mr Adura from ASIS.


    2011-02-12

    Question 3 Paper 3 Chemistry SPM 2010


    Actually, the question is quite direct. There are many possible experiment plan. In fact, in student's textbook, students were asked to plan an experiment to study whether copper (II) sulphate affect the rate of reaction between zinc and sulphuric acid too.

    Some useful guides when attempting this question:
    1. Give an example of acid & metal.
    2. How does metal react with acid? What is produced?
    3. How to do measure rate of reaction in an experiment? Hint: Rate of reaction is measured based on observable changes of quantity of reactant/product over a period of time. 
    4. What are the required information/data to compare the effect of catalyst on the rate of reaction?
    5. Try to imagine the materials & apparatus required.
    6. Draw diagram to show the set-up of apparatus for the experiment.
    7. Think of the steps to set-up the apparatus till recording data required.
    8. Write down your plan.
    9. Recheck your plan. Especially for materials, apparatus & procedure & tabulation of data. Students do forget some important point.
    Similar question was appeared in SPM 2005, click here. The candidates are asked to plan an experiment to study the effect of concentration on the rate of reaction between a named metal & a named acid. My students get confused when they looked at the question. The first idea popped out from the head was reaction between sodium thiosulphate & sulphuric acid which in fact a wrong plan.

    2011-02-11

    Molecular Model of Alkanes

    Alkanes are saturated hydrocarbons. Alkane molecules consist only carbon and hydrocarbon atoms only. The atoms are joined by covalent single bond.
    






    Some molecular models of few members of alkanes. Can you name them?

    5H students were happilly showing their molecular models after constructing few models of alkane members.
    5C students are calculating number of atoms present in an alkane molecule.

    Students are constructing the molecular model of decane in groups.

    A student proudly showed her completed handout after using the molecular model of alkane.

    2011-01-30

    Visitors from Jawa Tengah


    Recently a bus of teachers & students from Jawa Tengah visited my school. Initially, the visitors were planned to observe my chemistry class with 5H.  But it went out not as planned. Few teachers & students dropped by my chemistry class and stayed with us for a while.  At that moment, I was showing a video relating reaction between hydrogen & iodine. The girls were asked to explain the requirement for a chemical reaction. Luckily the lesson went well as planned.

    2011-01-29

    Scientists' Contribution towards Development of Atomic Structure


    1. J.J. Thomson discovered electron.
    2. Ernest Rutherford discovered the proton
    3. James Chadwick discovered the neutron.
    We get to know more about an atom thanks to their effort.

    In your opinion, how does an atom look like? How about a carbon atom?

    Please respond  by leaving your comments & names.

    2011-01-28

    Effect of Concentration of Sodium Thiosulphate on its Rate of Reaction with Sulphuric Acid

    5C students carried out their investigation to study the effect of concentration of sodium thiosulphate on its rate of reaction with sulphuric acid on 24 Jan 2011.

    Before the experiment, they were ready with their experiment plan. Most of them were able to write a satisfactory experiment plan. However, the aim of the experiment, problem statement were not specific.  Some even were not ready with their table. Hopefully they would improve after discussing with me.

    The students were able to carry out the experiment with correct technique & skills. Well done, 5C students!
    The student was taking time for mark 'X' dissapear from view.
     
    Cooperation is shown througout the experiment.
    
    The conical flask is swirled once sulphuric acid is added into sodium thiosulphate.

    Mark 'X' is observed from top of the conical flask. The other pair of students were discussing their data.

    2011-01-02

    Chemistry SPM 2010 Paper 1

    Chemistry SPM was on 6 Dec 2010, which is a week ago. As I go through the question paper in more details, the arrangement of the question was slightly different compared to the last few years. Normally questions involving calculation or more difficult question are arranged at later part. But this year the questions are seems more likely arranged according to topics in chemistry syllabus.

     

    Chapter

    No of Question

    2   Structure of atom                                    

    2

    3   Chemical Formulae & Equations

    3

    4   Periodic Table of Elements

    4

    5   Chemical Bonds

    6

    6   Electrochemistry                                     

    4

    7   Acid & Bases                                  

    5

    8   Salts                                                       

    2

    9   Manufacture Substances in Industry        

    5

    1   Rate of Reaction                                     

    4

    2   Carbon Compounds                               

    7

    3   Redox                                                    

    4

    4   Thermochemistry                                    

    3

    5   Chemicals for Consumer

    1

    For answer for this paper, please click here.