Why was there a need to promote population growth?
- Declining birth rate from the 1980s.
- Unattractive to multinational companies
- Ageing population
- Defence
DECLINING BIRTH RATE FROM THE 1980s.
-1980's, the fertility rate hit 1.82 children per woman.
-Showed that family planning policy to reduce birthrate was successful.
-Increase costs of living and marrying at later age led to the declining birth rates.
-More jobs were created in the industries,
therefore it needed a larger workforce to sustain the nation's development.
-The number of babies born were falling below the replacement value.
-There's a need to re-examine population policy,
as there may be potential problems a small population would pose.
UNATTRACTIVE TO MULTINATIONAL COMPANIES.
-With a small population Singapore would not produce enough talented people to sustain its development.
-Multinational corporations would find it difficult and more expensive to recruit Singaporeans,
as compared to the larger labour market in China.
-Singapore would be less attractive because of its smaller consumer market.
AGEING POPULATION.
-Fewer babies born each year means fewer young population.
-Number of older people proportionately larger,
leading to a ageing population.
-More resources needed to take care of the increasing number of senior citizens.
-Leading to an ageing population
DEFENCE
-Declining birthrate means fewer men to recruit for NS.
This will mean Singapore's Defence Force will be weaken.
Thursday, October 29, 2009
Saturday, October 24, 2009
Idioms
cost an arm and a leg -
be very expensive
These cakes are
delicious, but they cost
an arm and a leg.
keep one's chin up -
try to be cheerful
Keep your chin up. I'm
sure you'll make some
friends soon.
rule of thumb -
basic rule.
The rule of thumb is
that the students wear
black pants and white
shirts.
see eye to eye -
agree.
The couple don't see eye
to eye on how to train
their pets.
wash one's hands of something -
stop dealing with an issue or problem.
I'm washing my hands of
Mary's addiction. She is
going to have to get
some professional help.
thick in the head - not very intelligent
I'm a bit thick in the
head when it comes to
reading a map.
eager beaver -
a person who is excited about doing certain work
Ever since he got his
new drill set my husband
has been an eager beaver
around the house.
get the lion's share -
get the greatest percentage
My aunt got the lion's
share of the
inheritance.
let the cat out of the bag -
reveal a secret
Who let the cat out of
the bag about the
surprise party?
rat race -
fierce, competitive struggle for power, position etc
I'm ready to leave this
rat race and retire in
Mexico.
straight from the horse's mouth -
directly from the original source
I know Jenny is
pregnant, because I
heard it straight from
the horse's mouth.
smell a rat -
suspect
I asked my brothers not
to tell my parents that
I went out, but I could
smell a rat as soon as I
opened the door.
take the bull by the horns -
face a challenge or danger boldly
If you really think you
deserve a promotion,
you'll have to take the
bull by the horns.
cream of the crop -
the best
We hired the cream of
the crop to entertain us
at the Christmas party.
golden opportunity -
perfect chance
The models' conference
was a golden opportunity
for me to sell my beauty
products.
be very expensive
These cakes are
delicious, but they cost
an arm and a leg.
keep one's chin up -
try to be cheerful
Keep your chin up. I'm
sure you'll make some
friends soon.
rule of thumb -
basic rule.
The rule of thumb is
that the students wear
black pants and white
shirts.
see eye to eye -
agree.
The couple don't see eye
to eye on how to train
their pets.
wash one's hands of something -
stop dealing with an issue or problem.
I'm washing my hands of
Mary's addiction. She is
going to have to get
some professional help.
thick in the head - not very intelligent
I'm a bit thick in the
head when it comes to
reading a map.
eager beaver -
a person who is excited about doing certain work
Ever since he got his
new drill set my husband
has been an eager beaver
around the house.
get the lion's share -
get the greatest percentage
My aunt got the lion's
share of the
inheritance.
let the cat out of the bag -
reveal a secret
Who let the cat out of
the bag about the
surprise party?
rat race -
fierce, competitive struggle for power, position etc
I'm ready to leave this
rat race and retire in
Mexico.
straight from the horse's mouth -
directly from the original source
I know Jenny is
pregnant, because I
heard it straight from
the horse's mouth.
smell a rat -
suspect
I asked my brothers not
to tell my parents that
I went out, but I could
smell a rat as soon as I
opened the door.
take the bull by the horns -
face a challenge or danger boldly
If you really think you
deserve a promotion,
you'll have to take the
bull by the horns.
cream of the crop -
the best
We hired the cream of
the crop to entertain us
at the Christmas party.
golden opportunity -
perfect chance
The models' conference
was a golden opportunity
for me to sell my beauty
products.
The High Dive
"Don't do it, Leah!" I gazed down at the clear blue water from the top of the high dive, trying hard to wash away the fears that clogged my mind. I tried to swallow the lump stuck in my throat, disintegrate the tight knot in the pit of my stomach. I couldn't. 1
The water loomed below me--it was a long way down. I glanced up and caught the look in my friends' pleading eyes. Don't do it, don't do it, their voices reverberated in my mind. I had never even wanted to do this in the first place, but it was a dare. A dare made by myself. I had been afraid of the high dive all my life. When I was little, I'd sit in the shallow end watching the older kids stand in long lines just to go on, the loud thwacks echoing though the room as their bodies hit the water, each thwack sounding of pain and discomfort to my ears. They were brave, they were more courageous than I and I had always felt small next to them. This was something I had to do, to prove to everyone--and to prove to me--who I really was, that I was not a coward. 2
I looked behind me to to see a line of kids formed by the stepladder, with impatient glares crossing their faces. They waited.3
They were waiting for me, I realized. I peered down at my friends once more. They watched intently. Maybe I don't have to do this, I thought to myself. Maybe there was still just enough time to climb down, return to the wonderful comfort of standing on real ground. No, I couldn't do that. I'd be Leah the Small for the rest of my life, I'd be Leah the Chicken, Leah the Coward. I couldn't back away when I was so close. I couldn't.4
Squeezing my eyes shut, I took one trembling step and jumped. When I opened them again, I was falling toward the water, and for that split moment of my life, I felt my heart lift with limitless power, I felt wonderfully brave. I felt I was riding on golden wings, soaring through clouds and serenading the world below. For that split moment, I felt free. Then, thwack! and the feeling was--as if it were never there--completely gone.
The water loomed below me--it was a long way down. I glanced up and caught the look in my friends' pleading eyes. Don't do it, don't do it, their voices reverberated in my mind. I had never even wanted to do this in the first place, but it was a dare. A dare made by myself. I had been afraid of the high dive all my life. When I was little, I'd sit in the shallow end watching the older kids stand in long lines just to go on, the loud thwacks echoing though the room as their bodies hit the water, each thwack sounding of pain and discomfort to my ears. They were brave, they were more courageous than I and I had always felt small next to them. This was something I had to do, to prove to everyone--and to prove to me--who I really was, that I was not a coward. 2
I looked behind me to to see a line of kids formed by the stepladder, with impatient glares crossing their faces. They waited.3
They were waiting for me, I realized. I peered down at my friends once more. They watched intently. Maybe I don't have to do this, I thought to myself. Maybe there was still just enough time to climb down, return to the wonderful comfort of standing on real ground. No, I couldn't do that. I'd be Leah the Small for the rest of my life, I'd be Leah the Chicken, Leah the Coward. I couldn't back away when I was so close. I couldn't.4
Squeezing my eyes shut, I took one trembling step and jumped. When I opened them again, I was falling toward the water, and for that split moment of my life, I felt my heart lift with limitless power, I felt wonderfully brave. I felt I was riding on golden wings, soaring through clouds and serenading the world below. For that split moment, I felt free. Then, thwack! and the feeling was--as if it were never there--completely gone.
A Mother's Love
Nothing can come close to the love that a mother feels for her children. Most women are inherently excellent mothers. Women carry their young before they are born and then continue to nurture them throughout their childhood and even into adulthood. Mothers make sure that their children are safe and happy throughout their childhood. It is the unconditional love that a mother feels that drives these feelings. It is hard to describe the feeling that a mother has towards her children. In fact, most people do not understand unless they become a mother themselves. Raising children comes with its own share of frustrations, from the needy new born baby that requires regular care to the sullen teenager, a mother's job is anything but easy. A famous saying states that "God could not be everywhere and so he invented mothers", these words are a great inspiration to mothers across the world. When all is well, a mother puts her children before anything else, including their own comfort and happiness.
Mothers give an awful lot of support to their children, whether it involves very visible support or simple background encouragement. Not only do mothers support their children, but they also often hold the whole family structure together. This role is not always plain sailing. A mother can also be upset or hurt. Remember that a mother often takes the fallout for the toddler tantrums and the teenage angst. Despite this, mothers, generally, will love their children no matter what they do.
Mothers are meant to be the cheerleaders of their kids, sometimes in loud and visible ways, sometimes in sublet or unspoken ways in the background. Mothers are often the backbone of families. Mothers job is not always an easy one. Mothers have to make sacrifices. Mothers can have their hearts broken. Mothers must be the conscience of young children and are often the brunt of their anger and pain as they grow into adulthood. The great thing about mothers is that they usually understand and love their kids anyways.
Every year there is a day set aside to celebrate the role of a mother. Unsurprisingly, the day is called Mother's day. This day is a great opportunity for children of all ages to show their appreciation for the work of a mother. Gifts and cards, often handmade with care, are given as a sign of love.
Every year there is one special day put aside for mothers. What else could it be called but "Mothers Day."? This is the day that sons and daughters who are grown make the long distance calls or take their moms out for dinner. Mother's Day is a special day when mom gets the flowers she deserves. Mother's Day is a day when children stop and say thank you to mom for all she has done over the years. Young children make mothers homemade cards that bring tears to mother's eyes and make her realize that it is all worth it.
Describing a mother's love is virtually impossible. It is a feeling that can only truly be understood by those that experience it. In time, a mother's daughters will grow up to be mothers themselves.
Never underestimate the influence that a mother has over a child. It may not always appear this way, but children look to their mother for guidance on how they should deal with situations. On the rare occasions that a mother is unable to look after their children, maybe through illness or death, it can have a tragic impact on the life of the children.
Mothers have incredible power over their children that they must be respect. It is a tragedy for a child when the mother is not someone who looks after the child properly. It is a tragedy when a child or children lose their mother's at a young age.
Mothers give an awful lot of support to their children, whether it involves very visible support or simple background encouragement. Not only do mothers support their children, but they also often hold the whole family structure together. This role is not always plain sailing. A mother can also be upset or hurt. Remember that a mother often takes the fallout for the toddler tantrums and the teenage angst. Despite this, mothers, generally, will love their children no matter what they do.
Mothers are meant to be the cheerleaders of their kids, sometimes in loud and visible ways, sometimes in sublet or unspoken ways in the background. Mothers are often the backbone of families. Mothers job is not always an easy one. Mothers have to make sacrifices. Mothers can have their hearts broken. Mothers must be the conscience of young children and are often the brunt of their anger and pain as they grow into adulthood. The great thing about mothers is that they usually understand and love their kids anyways.
Every year there is a day set aside to celebrate the role of a mother. Unsurprisingly, the day is called Mother's day. This day is a great opportunity for children of all ages to show their appreciation for the work of a mother. Gifts and cards, often handmade with care, are given as a sign of love.
Every year there is one special day put aside for mothers. What else could it be called but "Mothers Day."? This is the day that sons and daughters who are grown make the long distance calls or take their moms out for dinner. Mother's Day is a special day when mom gets the flowers she deserves. Mother's Day is a day when children stop and say thank you to mom for all she has done over the years. Young children make mothers homemade cards that bring tears to mother's eyes and make her realize that it is all worth it.
Describing a mother's love is virtually impossible. It is a feeling that can only truly be understood by those that experience it. In time, a mother's daughters will grow up to be mothers themselves.
Never underestimate the influence that a mother has over a child. It may not always appear this way, but children look to their mother for guidance on how they should deal with situations. On the rare occasions that a mother is unable to look after their children, maybe through illness or death, it can have a tragic impact on the life of the children.
Mothers have incredible power over their children that they must be respect. It is a tragedy for a child when the mother is not someone who looks after the child properly. It is a tragedy when a child or children lose their mother's at a young age.
Wednesday, October 21, 2009
ROCKY
"The world ain't all sunshine and rainbows.
It's a very mean and nasty place... and I don´t care how tough you are, it will beat you to your knees and keep you there permanently, if you let it. You, me or nobody, is gonna hit as hard as life.
But ain't about how hard you hit... It's about how hard you can get hit, and keep moving forward... how much you can take, and keep moving forward. That´s how winning is done.
Now, if you know what you worth, go out and get what you worth.
But you gotta be willing to take the hits.
And not pointing fingers saying: You ain´t what you wanna be because of him or her or anybody. Cowards do that and that ain´t you! You´re better than that!" (Rocky Balboa)
It's a very mean and nasty place... and I don´t care how tough you are, it will beat you to your knees and keep you there permanently, if you let it. You, me or nobody, is gonna hit as hard as life.
But ain't about how hard you hit... It's about how hard you can get hit, and keep moving forward... how much you can take, and keep moving forward. That´s how winning is done.
Now, if you know what you worth, go out and get what you worth.
But you gotta be willing to take the hits.
And not pointing fingers saying: You ain´t what you wanna be because of him or her or anybody. Cowards do that and that ain´t you! You´re better than that!" (Rocky Balboa)
Monday, October 19, 2009
PE THEORY
SKILL: Ability to use knowledge of expertise to succeed efficiently and effectively in achieving a particular objective.
REACTION TIME: Ability to respond quickly to stimuli
COORDINATION: Ability to use the senses and body parts in order to perform motor tasks smoothly and accurately.
SPEED: Ability to perform a movement quickly
POWER: Ability to transfer energy swiftly into force
AGILITY: Ability to rapidly and accurately change the direction of the entire body in space
BALANCE: Ability to maintain equilibrium while standing or moving.
HEALTH: A complete state of Physical, Mental & Social well-bring and not merely the absence of disease of infirmity.
MUSCULAR STRENGTH: Ability to exert an external force or to lift a heavy weight.
BODY COMPOSITION: Relative percentage of muscle, fat, bone & other tissues of which the body is composed.
CARDIOVASCULAR ENDURANCE: Ability of the heart, blood vessels & respiratory system to supply fuel & oxygen to the muscles
MUSCULAR ENDURANCE: Ability of the muscles to repeatedly exert themselves
FLEXIBILITY: Having a wide range of motion in a joint.
VO2 MAX: The maximum amount of oxygen we can transport and use in one minute [ml/kh/min]
CREATINE PHOSPHATE : ATP ----> ADP + ENERGY
ANAEROBIC SYSTEM : GLUCOSE ----> ENERGY + LACTIC ACID
AEROBIC SYSTEM : GLUCOSE + OXYGEN ----> ENERGY + CO2 + H20
MOTIVATION: The drive to do well.
AROUSAL: State of readiness of the performer.
ANXIETY: The physiological state of Fear, Apprehension & Worry.
FITNESS: Ability to meet the demands of the environment.
CARDIOVASCULAR SYSTEM: The system that controls circulation of blood and transport of oxygen and nutrients to the cells of the body.
ARTERIES: Vessels which carry blood away from the heart.
VEINS: Vessels which carry blood back to the heart.
CAPILLARIES: Network of small vessels through which blood passes.
HEART RATE: Number of pulses our heart beats per minute [75bpm]
STROKE VOLUME: Volume of blood ejected from the heart in one minute [ml/beat]
CARDIAC OUTPUT: Volume of blood ejected from left ventricle in one minute [l/min]
BLOOD PRESSURE: Pressure needed to pump blood around the human body.
MAXIMUM HEART RATE: Maximum number of heart beats per minute [220 - age ]
RESPIRATION: Transporting oxygen to the cells of the body while removing waste products such as CO2.
OXYGEN DEBT: The supply of oxygen is greater than the demand.
MUSCULAR STRENGTH: Ability to exert an external force or lift a heavy weight.
PHYSIQUE: The size and weight of the body with regard of its composition such as muscle and fat.
SOMATO TYPES: Classifying the human body according to certain basic shape and built.
FAT-FREE WEIGHT: Weight of the body excluding fat but including organs.
DOPING: Illegal use of a drug to enhance sporting performance.
DRUGS: Usually used to treat illnesses but misused by athletes in order to artificially boost performance.
EXERCISE: Physical activity that improves health and fitness
SPORT: Organised contests involving physical activity between individuals / teams.
LEISURE: Free time in which you can choose what to do and when and where to do it.
RECREATION: Enjoyable activity that refreshes you and gives you more energy.
STRESS: Tension in the body and mind.
OPEN SPORT: Allows both amatuers and professionals to compete against one another.
REACTION TIME: Ability to respond quickly to stimuli
COORDINATION: Ability to use the senses and body parts in order to perform motor tasks smoothly and accurately.
SPEED: Ability to perform a movement quickly
POWER: Ability to transfer energy swiftly into force
AGILITY: Ability to rapidly and accurately change the direction of the entire body in space
BALANCE: Ability to maintain equilibrium while standing or moving.
HEALTH: A complete state of Physical, Mental & Social well-bring and not merely the absence of disease of infirmity.
MUSCULAR STRENGTH: Ability to exert an external force or to lift a heavy weight.
BODY COMPOSITION: Relative percentage of muscle, fat, bone & other tissues of which the body is composed.
CARDIOVASCULAR ENDURANCE: Ability of the heart, blood vessels & respiratory system to supply fuel & oxygen to the muscles
MUSCULAR ENDURANCE: Ability of the muscles to repeatedly exert themselves
FLEXIBILITY: Having a wide range of motion in a joint.
VO2 MAX: The maximum amount of oxygen we can transport and use in one minute [ml/kh/min]
CREATINE PHOSPHATE : ATP ----> ADP + ENERGY
ANAEROBIC SYSTEM : GLUCOSE ----> ENERGY + LACTIC ACID
AEROBIC SYSTEM : GLUCOSE + OXYGEN ----> ENERGY + CO2 + H20
MOTIVATION: The drive to do well.
AROUSAL: State of readiness of the performer.
ANXIETY: The physiological state of Fear, Apprehension & Worry.
FITNESS: Ability to meet the demands of the environment.
CARDIOVASCULAR SYSTEM: The system that controls circulation of blood and transport of oxygen and nutrients to the cells of the body.
ARTERIES: Vessels which carry blood away from the heart.
VEINS: Vessels which carry blood back to the heart.
CAPILLARIES: Network of small vessels through which blood passes.
HEART RATE: Number of pulses our heart beats per minute [75bpm]
STROKE VOLUME: Volume of blood ejected from the heart in one minute [ml/beat]
CARDIAC OUTPUT: Volume of blood ejected from left ventricle in one minute [l/min]
BLOOD PRESSURE: Pressure needed to pump blood around the human body.
MAXIMUM HEART RATE: Maximum number of heart beats per minute [220 - age ]
RESPIRATION: Transporting oxygen to the cells of the body while removing waste products such as CO2.
OXYGEN DEBT: The supply of oxygen is greater than the demand.
MUSCULAR STRENGTH: Ability to exert an external force or lift a heavy weight.
PHYSIQUE: The size and weight of the body with regard of its composition such as muscle and fat.
SOMATO TYPES: Classifying the human body according to certain basic shape and built.
FAT-FREE WEIGHT: Weight of the body excluding fat but including organs.
DOPING: Illegal use of a drug to enhance sporting performance.
DRUGS: Usually used to treat illnesses but misused by athletes in order to artificially boost performance.
EXERCISE: Physical activity that improves health and fitness
SPORT: Organised contests involving physical activity between individuals / teams.
LEISURE: Free time in which you can choose what to do and when and where to do it.
RECREATION: Enjoyable activity that refreshes you and gives you more energy.
STRESS: Tension in the body and mind.
OPEN SPORT: Allows both amatuers and professionals to compete against one another.
Sunday, September 27, 2009
CHEMISTRY KEY WORDS
Element: A pure substance that is only made up of one type of atom
Atoms: The smallest particles of an element which can still keep the chemical properties of that element.
Molecules: A pure substance made up of two or more atoms covalently bonded.
Compound: A pure substance made up of two or more different elements chemically combined in a fixed ratio.
Mixture: made up of two or more substances that are physically combined.
KINETIC THEORY
Oxygen has a higher molecular mass than chlorine gas, hence it requires more energy for it to move and thus diffuse slower than chlorine gas.
SOLID: The particles are closely packed in a regular pattern. The particles vibrate about their fixed positions.
LIQUID: The particles are loosely packed together. The particles move at random, sliding over each other.
GAS: The particles are spread far apart. The particles move rapidly at random.
STRUCTURE AND BONDING.
MELTING POINT & BOILING POINT
Sodium chloride has a GIANT IONIC STRUCTURE that consists of strong electrostatic forces of attraction between ions. A lot of energy is needed to overcome these bonds, hence a high melting or boiling point.
Diamond has a GIANT COVALENT STRUCTURE that consists of strong covalent bonds between atoms. A lot of energy is needed to overcome these bonds, hence a high melting point or boiling point.
Oxygen has a SIMPLE COVALENT STRUCTURE that consists of weak intermolecular forces of attraction between molecules. Only little energy is needed to overcome these bonds, hence a low melting point or boiling point.
Copper has a giant metallic structure that consists of strong electrostatic forces of attraction between positive ions and a sea of free mobile valence electrons. A lot of energy is needed to overcome these bonds, hence a high melting or boiling point.
CHARGES.
NaCl & CuSO4
Sodium chloride has single charges while copper(II) sulfate has double charges. Hence copper(II) sulfate possess stronger electrostatic forces of attraction between Copper(II) ions and Sulfate ions. More energy is needed to overcome these bonds, hence a high melting point or boiling point.
ELECTRICAL CONDUCTIVITY.
Sodium chloride has a GIANT IONIC STRUCTURE that consists of sodium ions and chloride ions tightly bounded by strong electrostatic forces of attraction in fixed positions. Thus, there are no free mobile ions available for electricity.
* In an aqueous or molten state, the giant ionic structure is destroyed to release the sodium and chloride ions. These freely moving ions are able to conduct electricity as they move about in the molten liquid or aqueous solution.
Copper has a GIANT METALLIC STRUCTURE that consists of strong electrostatic forces of attraction between positive ions anda sea of free mobile valence electron. These free mobile delocalised electrons are able to carry electrical current from a negative to the positive terminal, hence giving copper the ability to conduct electricity.
Oxygen has a SIMPLE/GIANT COVALENT STRUCTURE that consists of oxygen/carbon atoms tightly bounded by strong covalent bonds. As the covalent compound is a neutral molecule, there are no free mobile ions or electrons available for conducting electricity.
*Diamond consists of a GIANT TETRAHYDRAL structure of carbon atoms where each carbon atom is covalently bonded to four other carbon atoms. As all the electrons are involved in covalent bonding, diamond cannot conduct electricity.
*Graphite consists of one carbon atom covalently bonded to three other carbon atoms in hexagonal laters of carbon atoms. One of the valence electron is not involved in covalent bonding and thus is FREE TO MOVE ABOUT to conduct electricity.
*Diamond has a giant covalent structure that consists of strong covalent bonds between atoms. A large amound of force is required to overcome these extremely strong bonds, hence it creates a lot of driction and be used as an abrasive.
*Graphite consists of hexagonal layers of carbon atoms held together by weak van der waals forces. A small amount of force applied can cause the layers of atoms to slide against each other, hence giving graphite the lubracative property.
ALLOYS AND MALLEABILITY
Copper has a giant metallic structure that consists of atoms arranged in a closely packed and orderly manner. When a considerable amount of force is applied, the layers of atoms slide over each other, allowing it to be malleable.
Addition of zinc disrupt the regular arrangement of the metal lattice due to different atomic radii of the zinc and copper atoms. Hence it is more difficult for the layers of atoms to slide against each other. Thus addition of zinc makes it stronger but less malleable.
REACTIVITY OF NOBLE GASES
Neon has already achieved a stable octet structure. It thus will have a very low tendency to gain or lose electrons as this will destroy its stable electronic configuration. Therefore, it is unreactive.
ACIDS, BASES & SALTS
STRONG AND WEAK ACIDS.
A strong acid is a substance which ionises completely in water to form a concentration of hydrogen ions.
A weak acid is a substance which ionises partially in water to form a low concentration of hydrogen ions.
A strong acid would react faster and cause a more vigorous reaction due to its higher concentration of hudrogen ions.
STRONG AND WEAK ALKALIS.
A strong alkali is a substance which ionises completely in water to form a high concentration of hydroxide ions.
A weak alkali is a substance which ionises partially in water to form a low concentration of hydroxide ions.
SALTS are compounds formed by the displaacement of hydrogen ions of an acid by a reactive metal.
REDOX REACTION
OXIDATION STATES
The oxidation state of X increased from -2 in XY to 0 in XZ, thus stating an oxidation reaction.
The oxidation state of Y decreased from 0 in XY to -2 in ZY, thus stating a reduction reaction.
Thus having both oxidation and reduction reactions, this is a redox reaction.
ELECTRON TRANSFER
An atom X gains/loses 5 electrons to form B. Reduction/Oxidation occurs.
REDUCING AGENT
X undergoes oxidation when the oxidation state of X increased from -2 in XY to 0 in XZ.
OXIDISING AGENT.
X undergoes reduction when the oxidation state of X decreased from 2 in XY to 0 in XZ
ENERGY CHANGES
The energy absorbed by the breaking of N Moles of X bonds and N moles of Y bonds is __kJ greater/lesser than the energy released by the forming of N Moles of X bonds and N moles of Y bonds, hence making it an exothermic/endothermic reaction
RATE OF REACTION
CATALYST
A catalyst is a substance which speeds up a reaction without itself being changed chemically and the mass remains the same before and after the reaction.
A catalyst speeds up the rate of reaction by offering an alternative reaction pathway that requies lower activation energy.
INCREASING TEMPERATURE
When the temperature increases, the X and Y molecules gain kinetic energy and move at higher speeds, this increases the frequency of effective collision between them. Thus the rate of reaction increases.
INCREASING PRESSURE
When the pressure increases, the X and Y molecules move at higher speeds and occur more unit volume. This increases the frequency of effective collisions between them. Thus the rate of reaction increases.
INCREASING CONCENTRATION
When the concentration increases, the amount of X and Y molecules per unit volume increases. This increases the frequency of effective collisions between them, thus the rate of reaction increases.
USING POWDERED REACTANTS OR CATALYST
This increases the surface area to volume ratio of the X and Y molecules available for reaction. The catalyst lowers the activation energy required for reaction to occur. This increases the frequency of effective collisions, thus the rate of reaction increases.
AIR
Carbon Monoxide: reacts more readily than oxygen with haemoglobin in red blood cells to form carboxyhaemoglobin, a stable compound. This inhibits the transportation of oxygen around the body, leading to dizziness or even death.
Acid Rain: Oxides of nitrogen/ Sulfer dioxide oxidises in air and dissolves in rainwater to form acid rain. It corrodes buildings and destroys vegetations.
Ozone Depletion: CFCs(chlorofluocarbons) destroy the ozone molecules, hence depleting the ozone layer, which prevents the penetration of harmful UV rays, which on prolonged exposure causes skin cancer.
How is nitrogen monoxide formed?
-In car engines where temperature is high, this provides energy for the bonds between nitrogen atoms to break and thus reacts with oxygen in the air to form nitrogen monoxide.
Global warming: increase in the volume of greenhouse gases causing heat to be absorbed by the greenhouse gases and trapped in the earth's atmosphere. Thus causes global warming which melts ice bergs, causing flooding in lowlands.
HABER PROCESS
Source of Hydrogen : cracking of crude oil fractions
Source of Nitrogen : Fractional distillation of liquidified air
REACTION CONDITIONS.
Haber Process: Fine Iron, 450C, 250 atm
Cracking of Hydrocarbon: Aluminium oxide/Silicon dioxide, 600C
Substitutions of Alkanes by Cl/Br: UV Light
Addition of HYdrogen to Alkenes to form Alkanes: Nickel, 200C
Addition of Steam to Alkenes to form Alcohols: Phosphoric (V) Acid, 300C, 60atm
Dehydration from Alcohols to Alkenes: Conc Sulfuric Acid, Warm
Formation of Ester: Conc Sulfuric Acid, Warm
Formation of Addition Polymers: 200C, 1000atm
Atoms: The smallest particles of an element which can still keep the chemical properties of that element.
Molecules: A pure substance made up of two or more atoms covalently bonded.
Compound: A pure substance made up of two or more different elements chemically combined in a fixed ratio.
Mixture: made up of two or more substances that are physically combined.
KINETIC THEORY
Oxygen has a higher molecular mass than chlorine gas, hence it requires more energy for it to move and thus diffuse slower than chlorine gas.
SOLID: The particles are closely packed in a regular pattern. The particles vibrate about their fixed positions.
LIQUID: The particles are loosely packed together. The particles move at random, sliding over each other.
GAS: The particles are spread far apart. The particles move rapidly at random.
STRUCTURE AND BONDING.
MELTING POINT & BOILING POINT
Sodium chloride has a GIANT IONIC STRUCTURE that consists of strong electrostatic forces of attraction between ions. A lot of energy is needed to overcome these bonds, hence a high melting or boiling point.
Diamond has a GIANT COVALENT STRUCTURE that consists of strong covalent bonds between atoms. A lot of energy is needed to overcome these bonds, hence a high melting point or boiling point.
Oxygen has a SIMPLE COVALENT STRUCTURE that consists of weak intermolecular forces of attraction between molecules. Only little energy is needed to overcome these bonds, hence a low melting point or boiling point.
Copper has a giant metallic structure that consists of strong electrostatic forces of attraction between positive ions and a sea of free mobile valence electrons. A lot of energy is needed to overcome these bonds, hence a high melting or boiling point.
CHARGES.
NaCl & CuSO4
Sodium chloride has single charges while copper(II) sulfate has double charges. Hence copper(II) sulfate possess stronger electrostatic forces of attraction between Copper(II) ions and Sulfate ions. More energy is needed to overcome these bonds, hence a high melting point or boiling point.
ELECTRICAL CONDUCTIVITY.
Sodium chloride has a GIANT IONIC STRUCTURE that consists of sodium ions and chloride ions tightly bounded by strong electrostatic forces of attraction in fixed positions. Thus, there are no free mobile ions available for electricity.
* In an aqueous or molten state, the giant ionic structure is destroyed to release the sodium and chloride ions. These freely moving ions are able to conduct electricity as they move about in the molten liquid or aqueous solution.
Copper has a GIANT METALLIC STRUCTURE that consists of strong electrostatic forces of attraction between positive ions anda sea of free mobile valence electron. These free mobile delocalised electrons are able to carry electrical current from a negative to the positive terminal, hence giving copper the ability to conduct electricity.
Oxygen has a SIMPLE/GIANT COVALENT STRUCTURE that consists of oxygen/carbon atoms tightly bounded by strong covalent bonds. As the covalent compound is a neutral molecule, there are no free mobile ions or electrons available for conducting electricity.
*Diamond consists of a GIANT TETRAHYDRAL structure of carbon atoms where each carbon atom is covalently bonded to four other carbon atoms. As all the electrons are involved in covalent bonding, diamond cannot conduct electricity.
*Graphite consists of one carbon atom covalently bonded to three other carbon atoms in hexagonal laters of carbon atoms. One of the valence electron is not involved in covalent bonding and thus is FREE TO MOVE ABOUT to conduct electricity.
*Diamond has a giant covalent structure that consists of strong covalent bonds between atoms. A large amound of force is required to overcome these extremely strong bonds, hence it creates a lot of driction and be used as an abrasive.
*Graphite consists of hexagonal layers of carbon atoms held together by weak van der waals forces. A small amount of force applied can cause the layers of atoms to slide against each other, hence giving graphite the lubracative property.
ALLOYS AND MALLEABILITY
Copper has a giant metallic structure that consists of atoms arranged in a closely packed and orderly manner. When a considerable amount of force is applied, the layers of atoms slide over each other, allowing it to be malleable.
Addition of zinc disrupt the regular arrangement of the metal lattice due to different atomic radii of the zinc and copper atoms. Hence it is more difficult for the layers of atoms to slide against each other. Thus addition of zinc makes it stronger but less malleable.
REACTIVITY OF NOBLE GASES
Neon has already achieved a stable octet structure. It thus will have a very low tendency to gain or lose electrons as this will destroy its stable electronic configuration. Therefore, it is unreactive.
ACIDS, BASES & SALTS
STRONG AND WEAK ACIDS.
A strong acid is a substance which ionises completely in water to form a concentration of hydrogen ions.
A weak acid is a substance which ionises partially in water to form a low concentration of hydrogen ions.
A strong acid would react faster and cause a more vigorous reaction due to its higher concentration of hudrogen ions.
STRONG AND WEAK ALKALIS.
A strong alkali is a substance which ionises completely in water to form a high concentration of hydroxide ions.
A weak alkali is a substance which ionises partially in water to form a low concentration of hydroxide ions.
SALTS are compounds formed by the displaacement of hydrogen ions of an acid by a reactive metal.
REDOX REACTION
OXIDATION STATES
The oxidation state of X increased from -2 in XY to 0 in XZ, thus stating an oxidation reaction.
The oxidation state of Y decreased from 0 in XY to -2 in ZY, thus stating a reduction reaction.
Thus having both oxidation and reduction reactions, this is a redox reaction.
ELECTRON TRANSFER
An atom X gains/loses 5 electrons to form B. Reduction/Oxidation occurs.
REDUCING AGENT
X undergoes oxidation when the oxidation state of X increased from -2 in XY to 0 in XZ.
OXIDISING AGENT.
X undergoes reduction when the oxidation state of X decreased from 2 in XY to 0 in XZ
ENERGY CHANGES
The energy absorbed by the breaking of N Moles of X bonds and N moles of Y bonds is __kJ greater/lesser than the energy released by the forming of N Moles of X bonds and N moles of Y bonds, hence making it an exothermic/endothermic reaction
RATE OF REACTION
CATALYST
A catalyst is a substance which speeds up a reaction without itself being changed chemically and the mass remains the same before and after the reaction.
A catalyst speeds up the rate of reaction by offering an alternative reaction pathway that requies lower activation energy.
INCREASING TEMPERATURE
When the temperature increases, the X and Y molecules gain kinetic energy and move at higher speeds, this increases the frequency of effective collision between them. Thus the rate of reaction increases.
INCREASING PRESSURE
When the pressure increases, the X and Y molecules move at higher speeds and occur more unit volume. This increases the frequency of effective collisions between them. Thus the rate of reaction increases.
INCREASING CONCENTRATION
When the concentration increases, the amount of X and Y molecules per unit volume increases. This increases the frequency of effective collisions between them, thus the rate of reaction increases.
USING POWDERED REACTANTS OR CATALYST
This increases the surface area to volume ratio of the X and Y molecules available for reaction. The catalyst lowers the activation energy required for reaction to occur. This increases the frequency of effective collisions, thus the rate of reaction increases.
AIR
Carbon Monoxide: reacts more readily than oxygen with haemoglobin in red blood cells to form carboxyhaemoglobin, a stable compound. This inhibits the transportation of oxygen around the body, leading to dizziness or even death.
Acid Rain: Oxides of nitrogen/ Sulfer dioxide oxidises in air and dissolves in rainwater to form acid rain. It corrodes buildings and destroys vegetations.
Ozone Depletion: CFCs(chlorofluocarbons) destroy the ozone molecules, hence depleting the ozone layer, which prevents the penetration of harmful UV rays, which on prolonged exposure causes skin cancer.
How is nitrogen monoxide formed?
-In car engines where temperature is high, this provides energy for the bonds between nitrogen atoms to break and thus reacts with oxygen in the air to form nitrogen monoxide.
Global warming: increase in the volume of greenhouse gases causing heat to be absorbed by the greenhouse gases and trapped in the earth's atmosphere. Thus causes global warming which melts ice bergs, causing flooding in lowlands.
HABER PROCESS
Source of Hydrogen : cracking of crude oil fractions
Source of Nitrogen : Fractional distillation of liquidified air
REACTION CONDITIONS.
Haber Process: Fine Iron, 450C, 250 atm
Cracking of Hydrocarbon: Aluminium oxide/Silicon dioxide, 600C
Substitutions of Alkanes by Cl/Br: UV Light
Addition of HYdrogen to Alkenes to form Alkanes: Nickel, 200C
Addition of Steam to Alkenes to form Alcohols: Phosphoric (V) Acid, 300C, 60atm
Dehydration from Alcohols to Alkenes: Conc Sulfuric Acid, Warm
Formation of Ester: Conc Sulfuric Acid, Warm
Formation of Addition Polymers: 200C, 1000atm
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