What are Soap and Detergent?

Most of my students are wondering how to identify soap and detergents? In fact, it's not easy to identify through their physical properties.  Soap and detergent are different in term of their chemical structures and their chemicals required during preparation. Hopefully the slideshow below will help you to to have a better idea.

Soap and Detergents

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What's in your food?

I find this book particular interesting. The author, Chia Joo Suan who is a food chemist give us a closer look at food through comprehensive and easy-to- read guide.

Food is important. We consumer food not only to sustain our life but also for their taste, nutritional and medicinal values. Are the food we are taking safe? Many food additives are added to enhance food quality. Do we realize what are they? Do these food additives bring any side effects to our health in the long term?

Chemicals for Consumer

The discovery of chemicals manufactured for consumers such as cleaning agents, food additives and medicines has helped us improve our health and standard of living. Today, different type of these chemicals are produced to meet the needs and preferences of consumers. Therefore, understanding the chemistry of these chemicals will help a consumer select and use them wisely.

Hopefull this holiday assignment will make you realise the importance of many chemicals available in your daily life.  Any doubt, don't be hesitate to ask. Enjoy your holidays!

Chemistry Review 2009

   The 2009 School Year at last comes to the end.  This is the first year I teach in this school.  5C, 5F, 4D & 4E were my students . At first, I found it was a whole new experience to teach in a all girls school.  Anyhow, I like my girls and happy with the their effort in their chemistry class.

  But i'm curious. Do my students like their chemistry lesson with me? What do they think about my teaching strategy/approach?  Knowing my students better would help me to improve in the coming school year.

I wish my students could email me their opinion to me, sweemoi@gmail.com. The follows are some guides what you could write:

1. Do you like your chemistry lesson?
2. What activity in the class you like the most? Computer simulation of abstract concepts, group experiment, module, topical questions, answering tips, pair/group discussion?
3. What are your suggestion to improve your chemistry lesson?
4. How frequent do you visit this blog? Everyday?
5. Which part in this blog do you like? Notes, tips, class activity, chemistry related website link, chemitry related knowledge?

How to get prepared for Paper 3 Chemistry SPM?

Many of my students keep on asking me about how to score Paper 3.  They are not sure whether they are ready for it or they are applying the correct learning strategies...

I think the most important is to get to know the format of Paper 3 first.

Different scientific skills are evaluated in this paper:

1. observing
2. classifying
3. measuring and using numbers
4. inferring
5. predicting
6. communicating
7. using space-time relationship
8. interpering data
9. defining operationally
10. controlling variables
11. hypothesizing
12. planning an experiment(problem stat/ement/aim of experiment, hypothesis/variables, materials & apparatus, procedure and tabulation of data)

   The scientifil skils are acquired by the students slowly when they plan, carry out experiments and make a report in their class.  PEKA is another way of assessment to evaluate students' scientific skills and attitudes too.
 
  So, the best strategy I would suggest is to go through the above list and identify which one you are still weak in.  Go through the past year questions or trial question from different state and try to study why an answer for a particular skill is considered as excellent answer(Score 3).

All the best! All the SPM 2009 Candidates.

Volume of Gas

1 mol of any gases, as you name it, oxygen gas, helium gas, hydrogen gas, neon gas, etc.... occupy the same volume in the room condition.

This concept is known as molar volume at room condition, which is 24 dm³ mol^-1.

Question Analysis of Paper 3 Trial Chemistry 2009 from Different State

I have done some analysis on the questions from all the trial papers that I  have gathered. It seems that some  questions are quite popular. However, I haven't get trial papers from Penang and Sarawak.

Hopefully this analysis will help students who are trying their best effort before sitting the Chemistry paper on 8 Dec 2009

Question Analysis Of Paper 3 Trial Chemistry from Different State from sweemoi khor

Measuring

Measuring is one of the important skill in chemistry. In the chemistry laboratory, it's common to find various apparatus e.g.buretthe, stop watch, voltmeter, thermomether, etc.

Measuring is one of the scientific skill included in Paper 3 Chemistry SPM. After going through different exam papers, examples of apparatus that I have noticed are as follows:

• stop watch(2003, 2008)
• Ruler (2003)
• Electronic balance(2004)
• Thermometer(2005, 2006, 2007)
• Buret
• Voltmeter

In order to score in this section, remember :

• write the value of the measurement according to the accuracy of the apparatus. E.g. buretthe reading has 2 decimal places.
• All the values must be consistent and with units.E.g. the unit for buretthe reading is cm3. Please ensure all reading recorded with 2 decimal places.

Measuring

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Any doubts with the measurement, please leave your comments here. All the best!

Question Analysis for Paper 2 & Paper 3 Trial SPM 2019 from Different States

Thousands thanks to

• Hanna & Hanni who have contributed their analysis for Trial Kelantan paper.
• Dhiya who has sent her analysis for Trial Negeri Sembilan paper
• Anis Adibah who has comments on Trial Perlis paper. (Incomplete analysis on Paper 2)
• Syafiqah, Nazirah and Shakina who have posted their comments on Trial Kedah paper
• Liyana Yahaya and Rohiza comment on Mallaca Trial Paper
• Sofea and Syazwani  comment on Selangor Trial Paper
• Lisa and Najihah sent their comments on Perak Trial Paper.

The analysis will be updated from time to time...

Question Analysis for Trial SPM from Different States from sweemoi khor

Transfer of Electron at A Distance

Students find difficulties in answering question related to this topic.

• which electrode is the negative terminal/positive terminal?
• mark the flow of electrons on the circuit
• which one is the oxidized substsance/releases electron/reducing agent?
• which one is the reduced substance/gain electron/oxizing agent.
• write half equation to show the reaction occur at each electrode
• write overall ionic equation for the reaction that occur in the U-tube
• Write observation.

Actually a student only need to remember some examples of oxidizing agent and reducing agent. Some examples of oxidizing agent and reducing agent are as follows

Lets take an examples when iron(II) sulphate solution and bromine water are used.

iron(II) sulphate solution is the reducing agent.

• iron(II) ion loses electron to form iron(III) ion.
• So, iron(II) ion is the oxidized substance.
• As electrons is produced, the electrode that dipped in the iron(II) sulphate solution is negative terminal
• electrons flow from this eletrode to another one through the external circuit.
• Observation: the green iron(II) sulphate solution turn yellow/brown
• Half equation: Fe²⁺ --> Fe³⁺ + e^-

Bromine water is the oxizing agent.

• electrode that dipped in bromine receive electron from the external circuit.
• So, this electrode is the positive terminal.
• Bromine gain electron, so bromine is reduced to bromide ion.
• So bromine is the reduced substance.
• Half equation: Br₂ + 2e^- --> 2Br^-
• Observation : the brown bromine water turn colourless.

As writing overall ionic equation, a student just need to add both half equation together.

Half equation 2Fe²⁺ + Br₂ --> 2Fe³⁺ + 2 Br^-

Try different questions to see how much you apply the tips given. All the best!

Photos shown my students were working in groups to set up apparatus to study transfer of electrons at at distance.

Moles

 

Concept of moles is an important concepts in chemistry. Students learn the basic concepts in Chapter 3 Chemical Formulae and Equation during form 4. Later, they relate the moles concepts with molarity of a solution in Chapter 7 Acids and Bases and Chapter 8 Salts.

 

During form 5, students are expected to apply the concept well in various numerical problems in Chapter 1 Rate of Reaction, Chapter 4 Thermochemistry.

Some common wrong concepts that I have come across:

• students thought that the moles is the same with molarity.
• they thought that volume refer for both solution and gas.

Plese my dear students, please study the relationship above thoroughly. Whenever come across any question related to this concepts, understand the questions and substitute the value given in the equation correctly.

Form 4 Final Examination SBP Year 2008

Dear form 4 students, please download  this 2008 final exam paper and have a look.

Perhaps it will help you

• to have a clearer picture about the examination format
• to identify which areas you are still weak in.

Any doubts about the foming finals, you're always to post  your comments here. 

All the best and enjoy your Deepavali holidays.

The picture is taken from http://annaleeblysse.blogspot.com/

Trial Chemistry Selangor 2009

Paper 1

Paper 2

Paper 3

Dear visitors, please leave comments about the questions after going through the papers. You're welcomed to leave any doubts/querries about the questions. Thanks.

Trial Chemistry Terengganu 2009

Paper 1; answer

Paper 2; answer

Paper 3; answer

Picture taken at Matang Mangrove Forest Reserve.

Trial Chemistry Negeri Sembilan 2009

Paper 1; answer

Paper 2; answer

Paper 3; answer

Picture taken at the Japanese Garden, Bukit Tinggi Resort.