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O-Level Singapore/O-Level Combine Chemistry and Physics Tuition/Physics Tutor

2015 Schedule – Combine Chemistry

S3 1.5 hrs SAT 9pm – 10.30pm

S3 1.5 hrs SAT 12.30pm – 2pm

S3 1.5 hrs SUN 12.30pm – 2pm

S4 2 hrs FRI 5pm – 7pm

S4 1.5 hrs SAT 12.30pm – 2pm

S4 1.5 hrs SUN 9am – 10.30pm

2015 Schedule – Combine Physics

S3 1.5 hrs SAT 10.30am – 12pm

S3 1.5 hrs SAT 2pm – 3.30pm

S3 1.5 hrs SUN 1pm – 2.30pm

S4 1.5 hrs FRI 4.30pm – 6pm

S4 1.5 hrs SAT 2pm – 3.30pm

S4 1.5 hrs SUN 10.30am – 12pm

Please contact Angie @ 96790479 or Mr Ong 98639633

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O-Level Additional Mathematics Tuition Singapore

2015 Schedule Additional Math

S3 1.5 hrs WED 4pm – 5.30pm

S4 2 hrs MON 4pm – 6pm

S4 2 hrs SUN 6pm – 8pm

Please contact Angie @ 96790479 or Mr Ong @ 98639633

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O Level E Maths Tuition Singapore/Tuition O Level E Maths/Tutor

2015 Schedule Elementary Math

S3 1.5 hrs WED 5.30pm – 7pm
S3 2 hrs FRI 3pm – 5pm
S4 1.5 hrs WED 7pm – 8.30pm
S4 2 hrs SUN 6pm – 8pm

Please contact Angie @ 96790479 or Mr Ong @ 98639633

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O Level E Maths Tuition Singapore/Tuition O Level E Maths/Tutor

Laws of Arithmetic

1. Commutative law

a+b=b+a
ab = ba

2. Associative law
a+(b+c)=(a+b)+c
a(bc) = (ab)c

3. Distributive law
a(b + c)= ab + ac
a(b — c) = ab — ac

For Exam based questions with full worked solution. Please contact Mr Ong @98639633

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O-Level Additional Mathematics Tuition Singapore

TOPIC 1 SIMULTANEOUS LINEAR EQUATIONS

Exam Tip 1
When we solve 2 simultaneous equations, the solutions are actually the intersection points (x and y coordinates) of the 2 intersecting curves (or straight lines) represented by the simultaneous equations.

For exam based question with full worked solution, please contact
@9863 9633

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O-Level Singapore/O-Level Combine Chemistry and Physics Tuition/Physics Tutor

Chapter 1 Measurement

Exam Tip 1
It is important to use SI units. A physical quantity without the appropriate unit is ambiguous, e.g. 5 units of length can represent 5 cm, 5 m or 5 km.
Many students are not careful enough in writing symbols. Do not use Kg (capital letter K for kilogram and M for metre.)

Exam Tip 2
Common e.g. of SI units using prefixes: millimetre (mm), centimetre (cm), kilometre (km), etc. Candidates must remember all the prefixes, their symbols and meanings.

Exam Tip 3
When using graphical method to find the resultant force of two forces.
The length of the diagonal in the diagram is not the actual resultant in most cases. Students need to refer to the scale chosen to calculate the resultant.

Exam Tip 4
A student has been asked to calculate the volume of a piece of wire, which is about 80 cm long and about 0.2 cm in diameter.
Which measuring instruments should the student use?

To answer a question like this, candidates need to know the accuracy of different measuring instruments

Exam Tip 5
The INSIDE jaws of a pair of vernier calipers can be used to measure the internal diameter of measuring cylinder and beaker.

If you need help in the above topics, please contact Angie @96790479 or Mr Ong @98639633

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O-Level Singapore/O-Level Combine Chemistry and Physics Tuition/Physics Tutor

TOPIC 1 EXPERIMENTAL CHEMISTRY

Exam Tip 1
Burettes and pipettes are both used to measure accurate volumes of liquids because they have been accurately calibrated.
Pipettes are calibrated to measure fixed volumes such as 10.0 cm3, 25.0 cm3. Burettes measure up to an accuracy of 0.1 cm3.

Exam Tip 2
When mixture gasses passed into sodium hydroxide, sodium hydroxide reacts with the sulphur dioxide to form a salt and water. Aqueous bromine reacts with ethene to form a saturated compound. What remains is oxygen that is collected over water. Oxygen supports combustion, hence relights a glowing splint.

Exam Tip 3
Oxygen can be collected over water because it is only slightly soluble in water.

Exam Tip 4
Insoluble salts such as copper(II) oxide, lead(II) iodide are separated from water by filtration.
The filter paper has tiny holes (called pores) that enable the particles of liquid (e.g. water, ink dyes, dissolved sodium chloride) to pass through, retaining behind the larger solid particles (e.g. sand, copper(II) oxide).

Exam Tip 5
A saturated solution is one that contains the maximum amount of solute that can possibly dissolve in it at a given temperature. A hot solution can dissolve more solute than a cold one. Hence, on cooling, the bulk of the solute is obtained as crystals.

A hot saturated solution gives large crystals when cooled slowly e.g. cooling at room temperature gives larger crystals compared to freezing. This is because in freezing, particles in a saturated solution have a shorter period of time to pack closer together to form a larger crystal.

Crystals can be re-crystallised (that is dissolved again in the same solvent, then repeating the entire crystallisation process) in order to obtain purer crystals. After crystallisation, the crystals can be weighed and the percentage purity of the impure salt can be calculated using:

Mass of salt obtained Purity =
(Mass of the salt obtained / Initial mass of impure salt) x 100%

If you need help in the O level Chemistry, please contact Angie @96790479 or Mr Ong 98639633

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O Level Chemistry Tuition Singapore/Chemistry O Level Tuition/Tutor

TOPIC 1 EXPERIMENTAL CHEMISTRY

Exam Tip 1
Burettes and pipettes are both used to measure accurate volumes of liquids because they have been accurately calibrated.
Pipettes are calibrated to measure fixed volumes such as 10.0 cm3, 25.0 cm3. Burettes measure up to an accuracy of 0.1 cm3.

Exam Tip 2
When mixture gasses passed into sodium hydroxide, sodium hydroxide reacts with the sulphur dioxide to form a salt and water. Aqueous bromine reacts with ethene to form a saturated compound. What remains is oxygen that is collected over water. Oxygen supports combustion, hence relights a glowing splint.

Exam Tip 3
Oxygen can be collected over water because it is only slightly soluble in water.

Exam Tip 4
Insoluble salts such as copper(II) oxide, lead(II) iodide are separated from water by filtration.
The filter paper has tiny holes (called pores) that enable the particles of liquid (e.g. water, ink dyes, dissolved sodium chloride) to pass through, retaining behind the larger solid particles (e.g. sand, copper(II) oxide).

Exam Tip 5
A saturated solution is one that contains the maximum amount of solute that can possibly dissolve in it at a given temperature. A hot solution can dissolve more solute than a cold one. Hence, on cooling, the bulk of the solute is obtained as crystals.

A hot saturated solution gives large crystals when cooled slowly e.g. cooling at room temperature gives larger crystals compared to freezing. This is because in freezing, particles in a saturated solution have a shorter period of time to pack closer together to form a larger crystal.

Crystals can be re-crystallised (that is dissolved again in the same solvent, then repeating the entire crystallisation process) in order to obtain purer crystals. After crystallisation, the crystals can be weighed and the percentage purity of the impure salt can be calculated using:

Mass of salt obtained Purity =
(Mass of the salt obtained / Initial mass of impure salt) x 100%

If you need help in the O level Chemistry, please contact Angie @96790479 or Mr Ong 98639633

[admin]

O-Level Singapore/O-Level/Pure Physics Tuition/Physics Tutor

Chapter 1 Measurement

Exam Tip 1
It is important to use SI units. A physical quantity without the appropriate unit is ambiguous, e.g. 5 units of length can represent 5 cm, 5 m or 5 km.
Many students are not careful enough in writing symbols. Do not use Kg (capital letter K for kilogram and M for metre.)

Exam Tip 2
Common e.g. of SI units using prefixes: millimetre (mm), centimetre (cm), kilometre (km), etc. Candidates must remember all the prefixes, their symbols and meanings.

Exam Tip 3
When using graphical method to find the resultant force of two forces.
The length of the diagonal in the diagram is not the actual resultant in most cases. Students need to refer to the scale chosen to calculate the resultant.

Exam Tip 4
A student has been asked to calculate the volume of a piece of wire, which is about 80 cm long and about 0.2 cm in diameter.
Which measuring instruments should the student use?

To answer a question like this, candidates need to know the accuracy of different measuring instruments

Exam Tip 5
The INSIDE jaws of a pair of vernier calipers can be used to measure the internal diameter of measuring cylinder and beaker.

If you need help in the above topics, please contact Angie @96790479 or Mr Ong @98639633

[admin]

A-Level Mathematics Tuition Singapore/JC Maths/H2 Math Tuition and Tutor

Binomial Expansion Concept

Concept 1 : Partial fractions

Use of partial fractions to provide simplification of expression before expansion.

The partial fractions decomposition can be found in MF15.

Concept 2 : Recognise the difference between the Binomial Theorem & Binomial
Series.

Binomial Theorem formula can only be used for expansion of (a + b)^n , where n is positive integer. The expansion works for any value of a and b

Knowing the range of values where Binomial Series is valid Expansion lxl < 1

Please contact Mr Ong @98639633 if you need help in Mathematics

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A-Level Economics Tuition Singapore/H2/H1 Economics Tuition

General Tips for Writing Essay on “Which Goal is the most important?”

I) Framework = S + C + C

A) S = Severity of the problem
You need to write on two things:
i) Which goal is currently in the biggest trouble?
ii) What are the negative consequences if left unresolved? OR What
are the benefits of resolving the problem and achieving that goal?

B) C = Conflict with other goals
You need to write on one thing:
i) How does focusing on goal X lead to conflict with goal Y?

C) C = Characteristics/Conditions a country faces
You need to write on one thing:
i) How does focusing on goal X lead to achievement of goal Y?

Please contact Angie Hp 96790479 or Mr Ong 98639633 if you need help in Economics and complete Notes

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A-Level Physics Tuition Singapore/H2 Physics Tuition/JC Physics Tutor

Hi A-level/H2/JC Physics Tuition students

Mastering Qualitative Questions

Topic 1: Measurement Part 1

1. What are systematic / random errors? How can they be eliminated?

Systematic Errors

Errors of measurement which result in all readings being consistent overestimates or underestimates of its true value.

Cannot be reduced by taking repeated readings.

Can be reduced or eliminated by careful experimental design or good experimental techniques.

Examples: apparatus (zero errors, poor calibration), poor experimental technique (consistent parallax error), external factors (air resistance, background radioactive count rate).

Small systematic errors mean good accuracy.

Random Errors

Errors of measurement which cause an unpredictable scatter of readings about a mean value.

Can be reduced by taking repeated readings and finding the average

Cannot be eliminated.

Examples: Inconsistent reaction time, random parallax error, environmental conditions (fluctuations in measurement), limited sensitivity of instruments.

Small random errors mean good precision.

If you need help in Physics please contact Mr Ong @98639633

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A-Level Biology Tuition Singapore/H2 Biology Tuition/JC Biology Tutor

TOPIC 2: DNA AND GENOMICS – Part 4

LEARNING OUTCOME

(d) Explain how a change in the sequence of the DNA nucleotide (gene mutation)
may affect the amino acid sequence in a protein, and hence the phenotype of the
organism e.g. sickle cell anaemia and cystic fibrosis. (Knowledge of substitution, addition, deletion and frameshift mutation may be required.)

ESSAY ANSWER

Sickle cell anaemia Mutation and effect on amino acid sequence and phenotype

Base substitution, where thymine is replaced with adenine in the beta haemoglobin gene at chromosome 11, where CTT which codes for polar
glutamic acid is substituted to CAT which codes for non-polar valine.

Glutamic acid and valine are amino acids with very different properties.
Glutamate is hydrophilic while valine is hydrophobic;

At low oxygen concentration, hydrophobic areas of different molecules would
stick together, resulting in HbS molecules polymerizing/ precipitating into
fibres. This will cause conformation changes to the tertiary structure of HbS
and affect the quarternary structure of the haemoglobin.

These long fibres distort the membrane of the red blood cell giving it its
distinct sickle shape.

Effect of sickle shape red blood cells

Sickle shaped cells blocked capillaries which will result in organ damage and
have a shorter lifespan due to increase in wear and tear.

Cystic fibrosis
Mutation and effect on amino acid sequence and phenotype

Cystic fibrosis is a genetic disorder affecting chromosome number 7, which is
caused by inheriting two recessive mutated alleles for Cystic Fibrosis
Transmembrane Conductance Regulator (CFTR).

CFTR is a transmembrane protein (located in the cell surface membrane) needed
for the regulation of diffusion of Cl− ions into and out of the epithelial cells.

Most cases of CF is caused by a mutation that results in the deletion of 3 base
pairs from the CFTR gene – codon number 508 in the mRNA sequence (F508).

As a result, the amino acid phenylalanine is missing at position 508 in the
protein. This in turn changes the 3D configuration of CFTR protein,
preventing the normal efflux of Cl- out from the cells, thus, Cl- ions accumulate in the cells.

Being negatively charged, the built-up of Cl- ions in the cells causes the influx of
Na+ ions into the cells to balance the negative charges
High concentration of ions inside the cell in turn prevents water from leaving the cells causing copious mucus production and cysts to develop in the lungs,
pancreas and liver

Effect of thick mucus

The thick mucus produced in CF patients clogs up the airways of the lungs, the
branches of the pancreatic duct and the bile duct from the liver into the gut.
This results in:

Repeated lung infections as mucus interferes with gaseous exchange in the
lungs.

Poor release of pancreatic enzymes as thick much clogs up the branches of
pancreatic duct.

Poor absorption of digested food as thick mucus clogs up the branches of bile
duct and pancreatic duct preventing the emulsification of fats and digestion of
carbohydrates.

Affected males are almost always infertile and females are frequently infertile.

CF sufferers have shorter than normal life expectancy. The shorter life
expectancy is due to their susceptibility to:

Bacteria lung infection especially pneumonia Development of enlarged liver / spleen. An inability to digest or absorb digested food products efficiently
The development of diabetes

For exam based questions and solutions, please contact Hp @9863 9633

For exam based questions and solutions, please contact Hp @9863 9633

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A Level GP/General Paper Tuition Singapore

Education vs. Schooling

The debate about public education misses a critical issue. Are students attending the public schools becoming well-educated or well-schooled? There’s a difference; one that is seminal in determining almost every other discussion about public education.

The current emphasis on test scores to determine whether a child is getting a good education has narrowed the definition of education. The assumption is: if children do well on standardized tests, then they are well educated. But that assumption may be false. Here’s why.

There’s more than a critical difference between being well-educated or well-schooled. Take a look at Enron, where individuals with degrees from highfalutin colleges and universities cooked the books, were deceitful in reporting their metrics, and bilked employees out of their retirement funds. All of them passed standardized tests and demonstrated acumen in reading, math, business and finance. The question is: were they well-educated?

Or take politics. There are many examples of administrations packed with the “best and brightest” individuals with law degrees and doctorates who have demonstrated their knowledge of facts, concepts, and theories. The Nixon, Reagan, Clinton and both Bush administrations have had smart people make foolish decisions and, even, unethical and illegal ones. Members of Congress, the vast majority with college degrees, succumb to the allure of financial influence and pressure from lobbyists and political insiders. The
question is: were they well-educated or well schooled?

Certainly in these examples, individuals are working in complex and high-pressure situations that call for more than literacy and simply mastery of facts or concepts. But all of us live in an increasingly complex world that requires more than “smarts” or “shrewdness”. What is necessary is wisdom, a term seldom heard today in discussions about education.

For complete articles Please contact Angie 96790479 or Mr Ong 98639633

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A-Level Chemistry Tuition Singapore/H2 Chemistry Tuition/JC Chemistry Tutor

Chemical Bonding

Sigma bond and pi bond

Depending on the way the orbitals overlap, the covalent bond formed is classified as either a sigma bond or a pi bond.

A sigma bond is formed when two orbitals overlap head-on. The electron density of a sigma bond is concentrated between the nuclei of the two bonding atoms.

3 Basic Examples:
(a) s–s overlap
(b) p–p overlap
(c) s–p overlap

A pi bond is formed when atomic orbitals overlap collaterally, i.e. side-on overlap

A double bond consists of a sigma bond and a pi bond e.g. for oxygen O2

A triple bond consists of a sigma bond and two pi bonds e.g. for nitrogen N2

The sigma bond is stronger than a pi bond because head-on overlap of charge cloud in a sigma bond has a greater degree of overlap than the side-onoverlap in a pi bond.

Remember:
• A single covalent bond consists of one sigma bond.
• A double covalent bond consists of one sigma bond and one pi  bond.
• A triple covalent bond consists of one sigma bond and two pi  bonds.

If you need complete note and more exam based questions with full worked solution, please contact @9863 9633

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