On Happiness

"Happiness isn't coins that you can save and spend.

You cannot withold the feeling, imaging that one day, some day, you'll experience all of it at one go. It isn't like pieces of sweets. It isn't a holiday or home that you save up for. By not feeling joy today, do you imagine that you can save it up and experience ecstasy in a distant future?

It cannot be delayed. It cannot be saved then spent.

It requires practice. You learn to be happier by feeling incrementally joyful each day. It is a muscle that must be exercised, lest it atrophy.

Learn to be happy. For only in learning so, will you be happy."

Using the Syllabuses

A respected teacher once asked, "how many of you actually read your syllabuses before?" The class was quiet. A few people raised their right hands hesitantly.

The teacher found out that about 20% of the students read their syllabuses before. 

"Do you all see why it is important for you to read the syllabuses? People who read their syllabuses know what may be tested. As a result, they are better prepared for their exams and, in general, do better." 
---------------------------------------------------------------
You are highly encouraged to download and print the syllabuses for your personal reference.

Read through them, know what will be tested. Before major examinations, use them as checklists. Tick against points that you're confident of scoring in. Highlight areas that you need to work on. 

Study smartly!

All the best for every exam and beyond :]

Source credit: SEAB

On Criticisms and Complaints


It was recently reported that for every criticism a baby received, it will take 7 compliments to maintain his self-esteem.

This was from an article on living life fully. The author has a nephew who criticised himself badly. This nephew had became so fearful of living that he cooped himself in his room, moribund and lethargic.

They tried a little experiment: the nephew has to count the number of times he self-criticises in a day.

The next day, after 3 hours of counting, he stopped. In that mere span of time, he had criticised himself 50 odd times. Not once, or even twice. Fifty.

We're our worst critics. We see flaws in ourselves that others don't. We beat ourselves up over what should have been and what could have been. Life was lived backwards.

We're criticised and we repeat these criticisms to ourselves, spraying salt on festering wounds.

Let's remember this: 1 criticism = 7 compliments.

While we're our harshest critics, we must remember to be our most ardent fans too.

Jokes II

The pessimist sees the glass half empty.
The optimist sees the glass half full. 
The chemist see the glass completely full, half in the liquid state and half in the vapor state.

Q: What is "HIJKLMNO"? 
A: H2O.
Q: What did the scientist say when he found 2 isotopes of helium? 
A: HeHe

To Differentiate between Alkane and Alkene

Alkane is a saturated hydrocabon. It does not have any C=C double bond.

Alkene is an unsaturated hydrocarhon. It has a C=C double bond.

When reddish-brown bromine is added to an alkane, the solution will turn and remain reddish-brown. However, when bromine is added to alkene, its reddish-brown colour will become colourless.

The explanation for this may be viewed here. The video (without any audio) of the experiments may be seen below. Take a look!

Being a Happy Teenager

Do you ever:
  • wish you were older?
  • wish you had more money?
  • get embarrassed by your parents?
  • wish you looked different?
  • wish you had different parents?
Do you ever feel "No one understands me."
Do you ever wonder "Will I fall in love?"
Do you sometimes want to drown your brothers and sisters?
Do you ever ask "Why do I have to learn all this stuff in school that I will probably never need?"
Do you ever wonder "Am I normal?"

- Being a Happy Teenager, Chapter 1 by Andrew Matthews

These are some doubts that we may face at different points of our lives. We may feel that we're the only ones in this world with these problems, a little suffocated and overwhelmed.

But this need not be the case.

We can examine some of our more restrictive thoughts and learn to rise above them. To grow and become happier, more receptive and wiser.

Consider reading Being a Happy Teenager by Andrew Matthews. This book offers some thoughtful advice on how to overcome personal challenges!

Ionic Equations

Ionic Equations

To write ionic equations, follow the following steps:

1) Write a balanced equation with state symbols.
2) Leave (s), (l) and (g) alone. Split (aq) into ions.
3) Cancel ions that appear on both sides of the equation - "spectator ions".

Check that your final answer is correct:
* No. and type of atoms on RHS = No. and type of atoms on LHS
* Sum of charges on RHS = Sum of charges on LHS

Some practice questions may be found here. You are highly encouraged to download the file and try it a few times!

Check their solutions here, yup.

Group 1 and 7 Periodicity

In the chapter Periodicity, under Group Trends, we observe that there are trends in the reactions of some elements. As such, these elements are in Groups.

For Group 1 Alkali Metals, we see that reactivity increases down the group. The reactions of these elements with water become increasingly vigorous. 


For Group 7 Halogens, a more reactive halogen will displace a less reactive halogen from its halide salt. The colour change may be observed below.


Take a look at the above videos!

On Life and Learning

Source credit: NYTimes eXaminer
(http://www.nytexaminer.com/2011/11/more-life-lessons-from-david-brooks/)  
 

And then, we convince ourselves that what we want aren’t really what we want. We rewrite the stories, paint over the partially coloured canvases and pretend that we don’t have those dreams.
Those dreams that we believe in and hope for and hanker after, they’re no longer.
It’s one of those quirks about failing. Once, we consider it an experience. Twice, a trial. And, if it happens too many times, we accept that it isn’t meant to be, that we aren’t good enough.
We tell ourselves that what we’ve are sufficient, that we should be contented.
This way, we soothe our envy. This way, we stop imagining. We allow some part within to fester and die. In sacrificing the possibilities – the what-ifs and what-may-bes – we become at peace.
- Wednesday, Feb 8, 2012

A professor reminded me of this post recently. We were talking about the nature of dreams – how to find the courage to strive for what we want and believe in. He noted that some Singaporeans gave up too easily.
Our chat was informal and insightful. There were no power relations; this professor didn’t talk down to me. He was older, more experienced, a Cambridge PhD holder, more accomplished in the arts and my lecturer. I was (and still am) woefully younger, inexperienced, an NUS undergraduate and his student. On any of these grounds, he could have made a patronising speech. He didn’t; for this, I’m grateful.
This professor has received awards in international arts festivals. He shared with me his life experiences:
1) Don’t over-rationalise away your ideas/ aspirations
Far too often, we find reasons for ourselves not to do something. We convince ourselves that our parents would be upset, that there are no ways we can make a living out of it. We believe others when they trivialise our aspirations.
Don’t do that.
It’s often easy to explain away our hopes – but how do we live with this state of denial? Please just try. Sometimes, the barriers you’ve built in your mind are far more formidable than the ones you’ll actually encounter.
2) Learn to be comfortable with who you are
Sit down, XY, and stop fidgeting. It’s really okay. I know that showing people your art is always a nerve-wrecking event. Up till now, whenever I show my films, I’ll cover my eyes with cupped hands and peep from the cracks between my fingers.
I’ve learnt, over time, to be more comfortable with who I am.
And you’ll have to learn as well. Don’t be so critical of yourself such that even you find it difficult to live with yourself.
3) Care for your efforts (even when others don’t)
Sometimes, people just don’t care about what you do. Back when I was in university, I was so excited after my one-year exchange and wanted to share my experiences with my friends. Then, I realised that they didn’t really want to know that much:
Friend: “How was the exchange?”
Me: “It was great and I -”
Friend: “So glad to hear that you had an awesome time! Let’s go and club now?”
You’d want to share your overseas adventures or the sweetness of success with people. You’d want to share an artwork, a program, an essay with your closed ones. These products, crystallised from hours of effort and thought.
But not all of them will appreciate or want that. You’ve to recognise that what’s important to you may not carry the same importance to the people around you and you’ve got to respect that. It’s critical that you appreciate your art, even when people around you just don’t care.
4) Lose yourself in your efforts
You need momentum in your art. You need to pour more individuality within. I can’t sense the person you’re in your art.
Most people who succeed in a brilliant manner, they lose themselves in their endeavors. It’s what they live for. They get all excited and hyped up over it. Is what you’re doing now what you’re living for?
5) Have confidence in failing repeatedly
It’s one thing to taste success, but quite another to taste failure. It feels that there is a social stigma attached with failing in Singapore. Look, failing is not a disease.
Learn to expect and accept failures. You’ll probably fail so often that it no longer matters.
True, failing hurts and, to some people, it hurts badly. But please don’t let the fear of failing stop you from trying.
6) Speak up
Speak up more. Fight for what you believe in. Singapore has this aura which makes days blend into one murk. I’ll wake up and think about what happened yesterday and I won’t remember it.
The country has this very comfortable, numbing environment that conditions people to be less aware of their surroundings. We walk to the pedestrian crossing, look at the traffic lights, wait for the green man. Cross. It was never like that when I was overseas. When I was in the Middle East, I could remember the stucco walls that I passed by daily, the nooks and crannies of every street.
This comfortable environment in Singapore has allowed many citizens to take their privileges for granted. In many ways, there’re top-notch policies that citizens fail to appreciate. This comfortable environment has also allowed Singaporeans to become less questioning, less probing. More willing to accept the status quo and the associated problems.
Don’t passively accept the truths that are handed to you. Question it, examine it. Understand it. Learn more about the nuances of issues. It’s okay that you are for or against certain policies. Just don’t do it blindly. And learn to speak up for what you have faith in.
7) Be open-minded to possibilities
People are so focused on pursuing the ideal job, so bent on the end results. They are so focused that they no longer see other possibilities.
In yesterday’s class, I asked, “who knows why you’re majoring in what you’re majoring now. Come on, raise your hands, don’t be shy.” Only one person raised her hand. I’ve done this with many classes before and many young people just don’t know what they want. It’s such a waste. I wish that NUS has a policy of allowing modules taken in the first year to be ungraded so that students can explore their interests.
I once had another student. Fantastic designer. On an overseas field trip, she showed us sketchbooks worth of fashion designs. And, can you guess her major?
She’s in Engineering. What’s a pity about such cases is that you people tend to do well in the system – straight As and all. There’s no need to be risk the safe and proven, for the unexplored, uncharted grounds.
8) Pursue your dreams when you’re young
I’m glad that you found what you want to do. Have the courage to do it, especially since you’re still young.
When you get older, you accumulate duties. You accumulate responsibilities and become tied down by them. I wish I’ve discovered what I now want to do when I was younger. It’d have been a lot easier.

And, above all, why do you wish to work? What’re you striving for? You need a compelling reason to push forth. Can you find one? Do you have one? Is this going to be a part of your life?
I hope that you’ll find the answers. Please try harder. And, all the best.
(The above article first appeared here.)

Chem Humour

A proton, neutron, and electron went out to dinner one night.  After a luxurious meal, the waiter brought the check to the proton and the electron.  The neutron was perplexed as to why the waiter didn't bring him his check.  So, he summoned the waiter to the table and asked him about it.

The waiter explained to the neutron, "For you, there's no charge!"
- On atomic structure

A small piece of ice which lived in a test tube fell in love with a Bunsen burner. "Bunsen! My flame! I melt whenever I see you," said the ice. 


The Bunsen burner replied,"It's just a phase you're going through".
- On phase changes

Two atoms are walking down the street.
Says one atom to the other, "Hey! I think I lost an electron!"
The other says, "Are you sure??"
"Yes, I'm positive!"
- On Ionisation

11.6 Macromolecules

(a) describe macromolecules as large molecules built up from small units, different macromolecules having different units and/or different linkages
(b) describe the formation of poly(ethene) as an example of addition polymerisation of ethene as the monomer
(c) state some uses of poly(ethene) as a typical plastic, e.g. plastic bags; clingfilm
(d) deduce the structure of the polymer product from a given monomer and vice versa
(e) describe nylon, a polyamide, and Terylene, a polyester, as condensation polymers and recognise the partial structures of nylon and Terylene
(Details of manufacture and mechanisms of these polymerisations are not required)
(f) state some typical uses of man-made fibres such as nylon and Terylene, e.g. clothing; curtain materials; fishing line; parachutes; sleeping bags
(g) describe the pollution problems caused by the disposal of non-biodegradable plastics
-Syllabus from SEAB
11.6 is only covered in O Level (Pure Chemistry) syllabus.

Feel free to post questions related to this topic below. Do include your name and class (i.e. John, 4E3). Also, if you know the answers to questions that your friends posted, do respond to them!

11.5 Carboxylic acids

O Level - Pure Chemistry

(a) describe the carboxylic acids as an homologous series containing the -CO2H group
(b) draw the structures of carboxylic acids, methanoic acid to butanoic acid and name the unbranched acids, methanoic to butanoic acids
(c) describe the carboxylic acids as weak acids, reacting with carbonates, bases and some metals
(d) describe the formation of ethanoic acid by the oxidation of ethanol by atmospheric oxygen or acidified potassium dichromate(VI)
(e) describe the reaction of a carboxylic acid with an alcohol to form an ester, e.g. ethyl ethanoate
(f) state some commercial uses of esters, e.g. perfumes; flavourings; solvents

O Level - Combined Chemistry

(a) describe the carboxylic acids as organic acids containing the –CO2H group
(b) describe the formation of ethanoic acid by the oxidation of ethanol by atmospheric oxygen or acidified potassium dichromate(VI)
- Syllabuses from SEAB
11.5 is not covered in N(A) Level syllabus.

Feel free to post questions related to this topic below. Do include your name and class (i.e. John, 4E3). Also, if you know the answers to questions that your friends posted, do respond to them!

11.4 Alcohols

O Level - Pure Chemistry

(a) describe the alcohols as an homologous series containing the -OH group
(b) draw the structures of alcohols, C1 to C4, and name the unbranched alcohols, methanol to
butanol
(c) describe the properties of alcohols in terms of combustion and oxidation to carboxylic acids
(d) describe the formation of ethanol by the catalysed addition of steam to ethene and by
fermentation of glucose
(e) state some uses of ethanol, e.g. as a solvent; as a fuel; as a constituent of alcoholic
beverages

O Level - Combined Chemistry

(a) describe the alcohols as an homologous series containing the -OH group
(b) draw the structures of unbranched alcohols, C1 to C3 and name the unbranched alcohols,
methanol to propanol
(c) describe the properties of alcohols in terms of combustion and oxidation to carboxylic acids
(d) describe the formation of ethanol by fermentation of glucose
- Syllabuses from SEAB
11.4 is not covered in N(A) Level syllabus.

Feel free to post questions related to this topic below. Do include your name and class (i.e. John, 4E3). Also, if you know the answers to questions that your friends posted, do respond to them!

11.3 Alkenes

O Level - Pure Chemistry

(a) describe the alkenes as an homologous series of unsaturated hydrocarbons with the general formula CnH2n
(b) draw the structures of branched and unbranched alkenes, C2 to C4, and name the unbranched alkenes, ethene to butene
(c) describe the manufacture of alkenes and hydrogen by cracking hydrocarbons and recognise that cracking is essential to match the demand for fractions containing smaller molecules from the refinery process
(d) describe the difference between saturated and unsaturated hydrocarbons from their molecular structures and by using aqueous bromine
(e) describe the properties of alkenes (exemplified by ethene) in terms of combustion, polymerisation and the addition reactions with bromine, steam and hydrogen
(f) state the meaning of polyunsaturated when applied to food products
(g) describe the manufacture of margarine by the addition of hydrogen to unsaturated vegetable oils to form a solid product

O Level - Combined Chemistry

(a) describe the alkenes as an homologous series of unsaturated hydrocarbons with the general formula CnH2n
(b) draw the structures of unbranched alkenes, C2 to C3 and name the unbranched alkenes, ethene to propene
(c) describe the manufacture of alkenes and hydrogen by cracking hydrocarbons and recognise that cracking is essential to match the demand for fractions containing smaller molecules from the refinery process
(d) describe the difference between saturated and unsaturated hydrocarbons from their molecular structures and by using aqueous bromine
(e) describe the properties of alkenes (exemplified by ethene) in terms of combustion and the addition reactions with bromine and hydrogen
(f) state the meaning of polyunsaturated when applied to food products
(g) describe the manufacture of margarine by the addition of hydrogen to unsaturated vegetable oils to form a solid product
(h) describe the formation of poly(ethene) as an example of addition polymerisation of ethene as the monomer
(i) state some uses of poly(ethene) as a typical plastic, e.g. plastic bags; clingfilm
(j) deduce the structure of the addition polymer product from a given monomer and vice versa
(k) describe the pollution problems caused by the disposal of non-biodegradable plastics

N(A) Level - Combined Chemistry

(a) describe the alkenes as an homologous series of unsaturated hydrocarbons with the general formula CnH2n
(b) draw the structures of unbranched alkenes, C2 to C3 and name the unbranched alkenes, ethene to propene
(c) describe the manufacture of alkenes and hydrogen by cracking hydrocarbons and recognise that cracking is essential to match the demand for fractions containing smaller molecules from the refinery process
(d) describe the difference between saturated and unsaturated hydrocarbons from their molecular structures and by using aqueous bromine
(e) describe the properties of alkenes (exemplified by ethene) in terms of combustion and the addition reactions with bromine and hydrogen
(f) state the meaning of polyunsaturated when applied to food products
(g) describe the manufacture of margarine by the addition of hydrogen to unsaturated vegetable oils to form a solid product
-Syllabuses from SEAB

Feel free to post questions related to this topic below. Do include your name and class (i.e. John, 4E3). Also, if you know the answers to questions that your friends posted, do respond to them!

11.2 Alkanes

O Level - Pure Chemistry

(a) describe an homologous series as a group of compounds with a general formula, similar chemical properties and showing a gradation in physical properties as a result of increase in the size and mass of the molecules, e.g. melting and boiling points; viscosity; flammability
(b) describe the alkanes as an homologous series of saturated hydrocarbons with the general formula CnH2n+2
(c) draw the structures of branched and unbranched alkanes, C1 to C4, and name the unbranched alkanes, methane to butane
(d) define isomerism and identify isomers
(e) describe the properties of alkanes (exemplified by methane) as being generally unreactive except in terms of burning and substitution by chlorine

O Level - Combined Chemistry

(a) describe an homologous series as a group of compounds with a general formula, similar chemical properties and showing a gradation in physical properties as a result of increase in the size and mass of the molecules, e.g. melting and boiling points; viscosity; flammability
(b) describe the alkanes as an homologous series of saturated hydrocarbons with the general formula CnH2n+2
(c) draw the structures of unbranched alkanes, C1 to C3 and name the unbranched alkanes, methane to propane
(d) describe the properties of alkanes (exemplified by methane) as being generally unreactive except in terms of burning and substitution by chlorine

N(A) Level - Combined Chemistry

(a) describe an homologous series as a group of compounds with a general formula, similar chemical properties and showing a gradation in physical properties as a result of increase in the size and mass of the molecules, e.g. melting and boiling points; viscosity; flammability
(b) describe the alkanes as an homologous series of saturated hydrocarbons with the general formula CnH2n+2
(c) draw the structures of unbranched alkanes, C1 to C3 and name the unbranched alkanes, methane to propane
(d) describe the properties of alkanes (exemplified by methane) as being generally unreactive except in terms of burning and substitution by chlorine
-Syllabuses from SEAB

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11.1 Fuels and Crude Oil

O Level - Pure Chemistry

(a) name natural gas, mainly methane, and petroleum as sources of energy
(b) describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation
(c) name the following fractions and state their uses
(i) petrol (gasoline) as a fuel in cars
(ii) naphtha as feedstock for the chemical industry
(iii) paraffin (kerosene) as a fuel for heating and cooking and for aircraft engines
(iv) diesel as a fuel for diesel engines
(v) lubricating oils as lubricants and as a sources of polishes and waxes
(vi) bitumen for making road surfaces
(d) state that the naphtha fraction from crude oil is the main source of hydrocarbons used as the feedstock for the production of a wide range of organic compounds
(e) describe the issues relating to the competing uses of oil as an energy source and as a chemical feedstock

O Level - Combined Chemistry

(a) name natural gas, mainly methane, and petroleum as sources of energy
(b) describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation
(c) name the following fractions and state their uses :
(i) petrol (gasoline) as a fuel in cars
(ii) naphtha as feedstock for the chemical industry
(iii) paraffin (kerosene) as a fuel for heating and cooking and for aircraft engines
(iv) diesel as a fuel for diesel engines
(v) lubricating oils as lubricants and as a source of polishes and waxes
(vi) bitumen for making road surfaces

N(A) Level - Combined Chemistry

(a) name natural gas, mainly methane, and petroleum as sources of energy
(b) describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation
(c) name the following fractions and state their uses
(i) petrol (gasoline) as a fuel in cars
(ii) naphtha as feedstock for the chemical industry
(iii) paraffin (kerosene) as a fuel for heating and cooking and for aircraft engines
(iv) diesel as a fuel for diesel engines
(v) lubricating oils as lubricants and as a source of polishes and waxes
(vi) bitumen for making road surfaces
- Syllabuses from SEAB

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10 Air

O Level - Pure Chemistry

(a) describe the volume composition of gases present in dry air as being approximately 79% nitrogen, 20% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide
(b) name some common atmospheric pollutants, e.g. carbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons
(c) state the sources of these pollutants as
(i) carbon monoxide from incomplete combustion of carbon-containing substances
(ii) nitrogen oxides from lightning activity and internal combustion engines
(iii) sulfur dioxide from volcanoes and combustion of fossil fuels
(d) describe the reactions used in possible solutions to the problems arising from some of the pollutants named in (b)
(i) the redox reactions in catalytic converters to remove combustion pollutants (see 6.1(d))
(ii) the use of calcium carbonate to reduce the effect of ‘acid rain’ and in flue gas desulfurisation
(e) discuss some of the effects of these pollutants on health and on the environment
(i) the poisonous nature of carbon monoxide
(ii) the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings
(f) discuss the importance of the ozone layer and the problems involved with the depletion of ozone by reaction with chlorine containing compounds, chlorofluorocarbons (CFCs)
(g) describe the carbon cycle in simple terms, to include
(i) the processes of combustion, respiration and photosynthesis
(ii) how the carbon cycle regulates the amount of carbon dioxide in the atmosphere
(h) state that carbon dioxide and methane are greenhouse gases and may contribute to global warming, give the sources of these gases and discuss the possible consequences of an increase in global warming

O Level - Combined Chemistry

(a) describe the volume composition of gases present in dry air as being approximately 79% nitrogen, 20% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide
(b) name some common atmospheric pollutants, e.g. carbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons
(c) state the sources of these pollutants as:
(i) carbon monoxide from incomplete combustion of carbon-containing substances
(ii) nitrogen oxides from lightning activity and internal combustion engines
(iii) sulfur dioxide from volcanoes and combustion of fossil fuels
(d) discuss some of the effects of these pollutants on health and on the environment:
(i) the poisonous nature of carbon monoxide
(ii) the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and its effects on respiration and buildings

N(A) Level - Combined Chemistry

(a) describe the volume composition of gases present in dry air as being approximately 79% nitrogen, 20% oxygen and the remainder being noble gases (with argon as the main constituent) and carbon dioxide
(b) name some common atmospheric pollutants, e.g. carbon monoxide; methane; nitrogen oxides (NO and NO2); ozone; sulfur dioxide; unburned hydrocarbons
(c) state the sources of these pollutants as:
(i) carbon monoxide from incomplete combustion of carbon-containing substances
(ii) nitrogen oxides from lightning activity and internal combustion engines
(iii) sulfur dioxide from volcanoes and combustion of fossil fuels
(d) discuss some of the effects of these pollutants on health and on the environment:
(i) the poisonous nature of carbon monoxide
(ii) the role of nitrogen dioxide and sulfur dioxide in the formation of ‘acid rain’ and
(iii) its effects on respiration and buildings
- Syllabuses from SEAB

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9.5 Iron

O Level - Pure Chemistry

(a) describe and explain the essential reactions in the extraction of iron using haematite, limestone and coke in the blast furnace
(b) describe steels as alloys which are a mixture of iron with carbon or other metals and how controlled use of these additives changes the properties of the iron, e.g. high carbon steels are strong but brittle whereas low carbon steels are softer and more easily shaped
(c) state the uses of mild steel, e.g. car bodies; machinery, and stainless steel, e.g. chemical plants; cutlery; surgical instruments
(d) describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water; prevention of rusting can be achieved by placing a barrier around the metal, e.g. painting; greasing; plastic coating; galvanising
(e) describe the sacrificial protection of iron by a more reactive metal in terms of the reactivity series where the more reactive metal corrodes preferentially, e.g. underwater pipes have a piece of magnesium attached to them

O Level - Combined Chemistry

(a) describe and explain the essential reactions in the extraction of iron using haematite, limestone and coke in the blast furnace
(b) describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water; prevention of rusting can be achieved by placing a barrier around the metal, e.g. painting; greasing; plastic coating

N(A) Level - Combined Chemistry

(a) describe and explain the essential reactions in the extraction of iron using haematite, limestone and coke in the blast furnace
(b) describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water; prevention of rusting can be achieved by placing a barrier around the metal, e.g. painting; greasing; plastic coating
- Syllabuses from SEAB

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9.4 Recycling of Metals

(a) describe metal ores as a finite resource and hence the need to recycle metals, e.g. recycling of iron
(b) discuss the social, economic and environmental issues of recycling metals
-Syllabuses from SEAB

9.3a is covered in N(A), O (Combined Chemistry) and O (Pure Chemistry) Levels syllabuses.

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9.3 Extraction of Metals

(a) describe the ease of obtaining metals from their ores by relating the elements to their
positions in the reactivity series
- Syllabus from SEAB

9.3a is covered in N(A), O (Combined Chemistry) and O (Pure Chemistry) Levels syllabuses.

Feel free to post questions related to this topic below. Do include your name and class (i.e. John, 4E3). Also, if you know the answers to questions that your friends posted, do respond to them!

9.2 Reactivity Series

O Level - Pure Chemistry

(a) place in order of reactivity calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc by reference to
(i) the reactions, if any, of the metals with water, steam and dilute hydrochloric acid,
(ii) the reduction, if any, of their oxides by carbon and/or by hydrogen
(b) describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction with
(i) the aqueous ions of the other listed metals
(ii) the oxides of the other listed metals
(c) deduce the order of reactivity from a given set of experimental results
(d) describe the action of heat on the carbonates of the listed metals and relate thermal stability to the reactivity series

O Level - Combined Chemistry

(a) place in order of reactivity calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc, by reference to the reactions, if any, of the metals with water, steam and dilute hydrochloric acid
(b) deduce the order of reactivity from a given set of experimental results

N(A) Level - Combined Chemistry

(a) place in order of reactivity calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc, by reference to the reactions, if any, of the metals with water, steam and dilute hydrochloric acid
(b) deduce the order of reactivity from a given set of experimental results
-Syllabus from SEAB

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9.1 Metals

O Level - Pure Chemistry

(a) describe the general physical properties of metals as solids having high melting and boiling points, malleable, good conductors of heat and electricity in terms of their structure
(b) describe alloys as a mixture of a metal with another element, e.g. brass; stainless steel
(c) identify representations of metals and alloys from diagrams of structures
(d) explain why alloys have different physical properties to their constituent elements

O Level - Combined Chemistry

(a) describe the general physical properties of metals as solids having high melting and boiling points, being malleable and good conductors of heat and electricity
(b) describe alloys as a mixture of a metal with another element, e.g. brass; stainless steel
(c) identify representations of metals and alloys from diagrams of structures

N(A) Level - Combined Chemistry

(a) describe the general physical properties of metals as solids having high melting and boiling points, being malleable and good conductors of heat and electricity
(b) describe alloys as a mixture of a metal with another element, e.g. brass; stainless steel
(c) identify representations of metals and alloys from diagrams of structures
- Syllabuses from SEAB

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8.2 Group Trends

O Level - Pure Chemistry

(a) describe lithium, sodium and potassium in Group I (the alkali metals) as a collection of relatively soft, low density metals showing a trend in melting point and in their reaction with water
(b) describe chlorine, bromine and iodine in Group VII (the halogens) as a collection of diatomic non-metals showing a trend in colour, state and their displacement reactions with solutions of other halide ions
(c) describe the elements in Group 0 (the noble gases) as a collection of monatomic elements that are chemically unreactive and hence important in providing an inert atmosphere, e.g. argon and neon in light bulbs; helium in balloons; argon in the manufacture of steel
(d) describe the lack of reactivity of the noble gases in terms of their electronic structures

O Level - Combined Chemistry

(a) describe lithium, sodium and potassium in Group I (the alkali metals) as a collection of relatively soft, low density metals showing a trend in melting point and in their reaction with water
(b) describe chlorine, bromine and iodine in Group VII (the halogens) as a collection of diatomic non-metals showing a trend in colour, state and their displacement reactions with solutions of other halide ions
(c) describe the lack of reactivity of the elements in Group 0 (the noble gases) in terms of their electronic structures

N(A) Level - Combined Chemistry

(a) describe lithium, sodium and potassium in Group I (the alkali metals) as a collection of relatively soft, low density metals showing a trend in melting point and in their reaction with water
(b) describe chlorine, bromine and iodine in Group VII (the halogens) as a collection of diatomic non-metals showing a trend in colour, state and their displacement reactions with solutions of other halide ions
- Syllabuses from SEAB

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8.1 Periodic Trends

O Level - Pure Chemistry

(a) describe the Periodic Table as an arrangement of the elements in the order of increasing proton (atomic) number
(b) describe how the position of an element in the Periodic Table is related to proton number and electronic structure
(c) describe the relationship between group number and the ionic charge of an element
(d) explain the similarities between the elements in the same group of the Periodic Table in terms of their electronic structure
(e) describe the change from metallic to non-metallic character from left to right across a period of the Period Table
(f) describe the relationship between group number, number of valency electrons and metallic/non-metallic character
(g) predict the properties of elements in Group I and VII using the Periodic Table

O Level - Combined Chemistry

(a) describe the Periodic Table as an arrangement of the elements in the order of increasing proton number (atomic number)
(b) describe how the position of an element in the Periodic Table is related to proton number and electronic structure
(c) explain the similarities between the elements in the same group of the Periodic Table in terms of their electronic structure
(d) describe the change from metallic to non-metallic character from left to right across a period of the Periodic Table
(e) describe the relationship between group number, number of valency electrons and metallic/non-metallic character
(f) predict the properties of elements in Group I and Group VII using the Periodic Table

N(A) Level - Combined Chemistry

(a) describe the Periodic Table as an arrangement of the elements in the order of increasing proton (atomic) number
(b) describe how the position of an element in the Periodic Table is related to proton number and electronic structure
(c) explain the similarities between the elements in the same group of the Periodic Table in terms of their electronic structure
(d) describe the change from metallic to non-metallic character from left to right across a period of the Periodic Table
(e) describe the relationship between group number, number of valency electrons and metallic/non-metallic character
(f) predict the properties of elements in Group I and Group VII using the Periodic Table
- Syllabuses from SEAB

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7.3 Ammonia

O Level - Pure Chemistry

(a) describe the use of nitrogen, from air, and hydrogen, from cracking oil, in the manufacture of
ammonia
(b) state that some chemical reactions are reversible, e.g. manufacture of ammonia
(c) describe the essential conditions for the manufacture of ammonia by the Haber process
(d) describe the displacement of ammonia from its salts
-Syllabuses from SEAB

This section is only covered in the O Level (Pure Chemistry) syllabus.

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7.2 Salts

O Level - Pure Chemistry

(a) describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques specified in Section 1.2(a)
(methods for preparation should include precipitation and titration together with reactions of acids with metals, insoluble bases and insoluble carbonates)
(b) describe the general rules of solubility for common salts to include nitrates, chlorides (including silver and lead), sulfates (including barium, calcium and lead), carbonates, hydroxides, Group I cations and ammonium salts
(c) suggest a method of preparing a given salt from suitable starting materials, given appropriate information

O Level - Combined Chemistry

(a) describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques specified in chemistry Section 1.2(a)
(methods for preparation should include precipitation and titration, together with reactions of acids with metals, insoluble bases and insoluble carbonates)
(b) suggest a method of preparing a given salt from suitable starting materials, given appropriate information

N(A) Level - Combined Chemistry

(a) describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques specified in Sections 1.2(a)
(methods for preparation should include precipitation and titration, together with reactions of acids with metals, insoluble bases and insoluble carbonates)
(b) suggest a method of preparing a given salt from suitable starting materials, given appropriate information
- Syllabuses from SEAB

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7.1 Acids and Bases

O Level - Pure Chemistry

(a) describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator and the pH scale
(c) describe qualitatively the difference between strong and weak acids in terms of the extent of ionisation
(d) describe the characteristic properties of acids as in reactions with metals, bases and carbonates
(e) state the uses of sulfuric acid in the manufacture of detergents and fertilisers; and as a battery acid
(f) describe the reaction between hydrogen ions and hydroxide ions to produce water as neutralisation
(g) describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
(h) describe the characteristic properties of bases in reactions with acids and with ammonium salts
(i) classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character
(j) classify sulfur dioxide as an acidic oxide and state its uses as a bleach, in the manufacture of wood pulp for paper and as a food preservative (by killing bacteria)

O Level - Combined Chemistry

(a) describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator and the pH scale
(c) describe the characteristic properties of acids as in reactions with metals, bases and carbonates
(d) describe the reaction between hydrogen ions and hydroxide ions to produce water as neutralisation
(e) describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
(f) describe the characteristic properties of bases as in reactions with acids and with ammonium salts
(g) classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character

N(A) Level - Combined Chemistry

(a) describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator and the pH scale
(c) describe the characteristic properties of acids as in reactions with metals, bases and carbonates
(d) describe the reaction between hydrogen ions and hydroxide ions to produce water as neutralisation
(e) describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
(f) describe the characteristic properties of bases as in reactions with acids and with ammonium salts
(g) classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character
- Syllabuses from SEAB

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6.2 Redox

O Level - Pure Chemistry

(a) define oxidation and reduction (redox) in terms of oxygen/hydrogen gain/loss
(b) define redox in terms of electron transfer and changes in oxidation state
(c) identify redox reactions in terms of oxygen/hydrogen gain/loss, electron gain/loss and changes in oxidation state
(d) describe the use of aqueous potassium iodide and acidified potassium dichromate(VI) in testing for oxidising and reducing agents from the resulting colour changes

O Level - Combined Chemistry

(a) define oxidation and reduction (redox) in terms of oxygen/hydrogen gain/loss
(b) define redox in terms of electron transfer and changes in oxidation state
(c) describe the use of aqueous potassium iodide and acidified potassium dichromate(VI) in testing for oxidising and reducing agents from the resulting colour changes
- Syllabuses from SEAB

This section is not covered in the N(A) Level (Combined Chemistry) syllabus.

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6.1 Speed of Reactions

O Level - Pure Chemistry

(a) describe the effect of concentration, pressure, particle size and temperature on the speeds of
reactions and explain these effects in terms of collisions between reacting particles
(b) define the term catalyst and describe the effect of catalysts (including enzymes) on the
speeds of reactions
(c) explain how pathways with lower activation energies account for the increase in speeds of
reactions
(d) state that some compounds act as catalysts in a range of industrial processes and that
enzymes are biological catalysts (see 5(b), 6.1(c) and 10(d))
(e) suggest a suitable method for investigating the effect of a given variable on the speed of a
reaction
(f) interpret data obtained from experiments concerned with speed of reaction

O Level - Combined Chemistry

(a) describe the effect of concentration, pressure, particle size and temperature on the speeds of
reactions and explain these effects in terms of collisions between reacting particles
(b) interpret data obtained from experiments concerned with speed of reaction
- Syllabuses from SEAB

This section is not covered in the N(A) Level (Combined Chemistry) syllabus.

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5 Energy from Chemicals

O Level - Pure Chemistry

(a) describe the meaning of enthalpy change in terms of exothermic (ΔH negative) and endothermic (ΔH positive) reactions
(b) represent energy changes by energy profile diagrams, including reaction enthalpy changes and activation energies (see 6.1(c),6.1(d))
(c) describe bond breaking as an endothermic process and bond making as an exothermic process
(d) explain overall enthalpy changes in terms of the energy changes associated with the breaking and making of covalent bonds
(e) describe hydrogen, derived from water or hydrocarbons, as a potential fuel, reacting with oxygen to generate electricity directly in a fuel cell (details of the construction and operation of a fuel cell are not required)

O Level - Combined Chemistry

(a) describe the term exothermic as a process or chemical reaction which transfers energy, often in the form of heat, to the surroundings and may be detected by an increase in temperature,
e.g. the reaction between sodium hydroxide and hydrochloric acid
(b) describe the term endothermic as a process or chemical reaction which takes in energy, often in the form of heat, from the surroundings and may be detected by a decrease in temperature,
e.g. the dissolving of ammonium nitrate in water
- Syllabuses from SEAB

This section is not covered in the N(A) Level (Combined Chemistry) syllabus.

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4 Electrolysis

O Level - Pure Chemistry

(a) describe electrolysis as the conduction of electricity by an ionic compound (an electrolyte), when molten or dissolved in water, leading to the decomposition of the electrolyte
(b) describe electrolysis as evidence for the existence of ions which are held in a lattice when solid but which are free to move when molten or in solution
(c) describe, in terms of the mobility of ions present and the electrode products, the electrolysis of molten sodium chloride, using inert electrodes
(d) predict the likely products of the electrolysis of a molten binary compound
(e) apply the idea of selective discharge based on
(i) cations: linked to the reactivity series (see 9.2)
(ii) anions: halides, hydroxides and sulfates (e.g. aqueous copper(II) sulfate and dilute sodium chloride solution (as essentially the electrolysis of water))
(iii) concentration effects (as in the electrolysis of concentrated and dilute aqueous sodium chloride)
(In all cases above, inert electrodes are used.)
(f) predict the likely products of the electrolysis of an aqueous electrolyte, given relevant information
(g) construct ionic equations for the reactions occurring at the electrodes during the electrolysis, given relevant information
(h) describe the electrolysis of aqueous copper(II) sulfate with copper electrodes as a means of purifying copper (no technical details are required)
(i) describe the electroplating of metals, e.g. copper plating, and state one use of electroplating
(j) describe the production of electrical energy from simple cells (i.e. two electrodes in an electrolyte) linked to the reactivity series (see 9.2) and redox reactions (in terms of electron transfer)
- Syllabus from SEAB

This section is covered only in the O Level (Pure Chemistry) syllabus.

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3 Formulae, Stoichiometry and the Mole Concept

O Level - Pure Chemistry

(a) state the symbols of the elements and formulae of the compounds mentioned in the syllabus
(b) deduce the formulae of simple compounds from the relative numbers of atoms present and vice versa
(c) deduce the formulae of ionic compounds from the charges on the ions present and vice versa
(d) interpret chemical equations with state symbols
(e) construct chemical equations, with state symbols, including ionic equations
(f) define relative atomic mass, Ar
(g) define relative molecular mass, Mr, and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses
(h) calculate the percentage mass of an element in a compound when given appropriate information
(i) calculate empirical and molecular formulae from relevant data
(j) calculate stoichiometric reacting masses and volumes of gases (one mole of gas occupies 24 dmat room temperature and pressure); calculations involving the idea of limiting reactants may be set
(The gas laws and the calculations of gaseous volumes at different temperatures and pressures are not required.)
(k) apply the concept of solution concentration (in mol/dm3or g/dm3) to process the results of volumetric experiments and to solve simple problems
(Appropriate guidance will be provided where unfamiliar reactions are involved.)
(l) calculate % yield and % purity

O Level - Combined Chemistry

(a) state the symbols of the elements and formulae of the compounds mentioned in the syllabus
(b) deduce the formulae of simple compounds from the relative numbers of atoms present and vice versa
(c) deduce the formulae of ionic compounds from the charges on the ions present and vice versa
(d) interpret chemical equations with state symbols
(e) construct chemical equations, with state symbols, including ionic equations
(f) define relative atomic mass, Ar
(g) define relative molecular mass, Mr, and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses
(h) calculate stoichiometric reacting masses and volumes of gases (one mole of gas occupies 24 dm3 at room temperature and pressure); calculations involving the idea of limiting reactants may be set
(The gas laws and the calculations of gaseous volumes at different temperatures and pressures are not required.)
(i) apply the concept of solution concentration (in mol/dm3 or g/dm3) to process the results of volumetric experiments and to solve simple problems
(Appropriate guidance will be provided where unfamiliar reactions such as redox are involved.
Calculations on % yield and % purity are not required.)

N(A) Level - Combined Chemistry

(a) state the symbols of the elements and formulae of the compounds mentioned in the syllabus
(b) deduce the formulae of simple compounds from the relative numbers of atoms present and vice versa
(c) deduce the formulae of ionic compounds from the charges on the ions present and vice versa
(d) interpret chemical equations with state symbols
(e) construct chemical equations, with state symbols, including ionic equations
(f) define relative atomic mass, Ar
(g) define relative molecular mass, Mr and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses
(h) perform calculations concerning reacting masses using simple proportions (calculations will not involve the mole concept)
- Syllabuses from SEAB

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