We're all mighty awesome!
We rock!
We rule!
We dominate the school!
We scream!
We shout!
We love to cheer out loud!
Cause we're so high
And We're too cool.
C2's the class
WHICH WILL ROCK THE SCHOOL!
GO C2! GO C2! Go,go, GO C2!
C2 is da bomb!
Our class xD
1; Amanda Teng [CHOIR, bronte]
2; Nathalie Au [GUIDES, curie]
3; Jermaine Boh [NPCC, fry,
VICE CHAIR PERSON!]
4; Tania Chang [GUIDES, keller]
5; Cheah Wenqi [CANOEING, pankhurst]
6; Theodora Chin [HOCKEY, bronte]
7; Chinmayi Bhatt [GUIDES, curie]
8; Claudia Chong [CHOIR, fry, literature rep]
9; Crystal Lim [DANCE, keller, maths rep]
10; Dinna Jayaweera Aratchi [SOFTBALL, pankhurst, sports rep]
11; Du Xinyi [ANGKLUNG, bronte]
12; Ermy Rukmana Bte Razali [ANGKLUNG,fry, HML rep]
13; Fang Xiao Ying [NCC, keller]
14; Fion Lee [BAND, pankhurst]
15; Fiorina Rayen [CHOIR, bronte, class aesthetics]
16; Jing Yi [BADMINTON, curie]
17; Michelle Heng [DANCE, fry]
18; Hufriya Unwalla [NPCC, keller]
19; Ilya Katrinnada Zubaidi [NPCC, pankhurst, history rep]
20; Jacqueline Gwee [I&E, bronte, IT rep]
21; Kang Tha Yang [BAND, curie]
22; Kirthika Muthiah [REDCROSS, fry]
23; Lai Shumin [I&E, keller, treasurer]
24; Lee Pei Pei [CHOIR, pankhurst]
25; Lim Yu Ru [ANGKLUNG, bronte]
26; Low Jo Ann [CHOIR, curie, chinese rep]
27; Low Zhi Xing Angela [ANKLUNG, fry]
28; Lun Weiru Samantha [DANCE, keller, math rep]
29; Madeline Ang [BAND, pankhurst]
30; Mah Nuo Nina [BADMINTON, bronte, it rep]
31; Marsiat Jahan [ELDDS, curie, geog rep]
32; Nadia Adila [BADMINTON, fry]
33; Nandhini [ANKLUNG, keller]
34; Nur Afifah Bte Agus [SOFTBALL, pankhurst]
35;
Nur Aisyah Bte Azman [bronte]
36; Nur Qistina Bte Aliffi [ANKLUNG, curie, chairperson]
37; Nurul Ayuni Bte Nordin [NPCC, fry, english rep]
38; Rachel Ker [DANCE, keller]
39; S. Meenakshi [CHOIR, pankhurst]
40; Vivega D/o Magendren [NCC, bronte, literature rep]
41; Xie Qihui Joyce [CANOEING, pankhurst, science rep]
Saturday, September 6, 2008 @ 10:30 AM
science notes :D
science notes :D
Chapter C2
Material:
Ø Substance used for making objects.
Ø Can be classified according to their physical properties:
1. Strength - ability to support heavy load without breaking or tearing
2. Harness – ability to scratch another object
3. Flexibility – ability to bend into without breaking and return to its original shape
4. Boiling point – temperature at which substance changes from liquid to gas
5. Melting point – temperature at which substance changes from solid to liquid
6. Electrical conductivity – how easily a substance allows electricity to pass through
7. Heat conductivity – how easily a substance allows heat to pass through
8. Malleability – ability to be bent and “beaten” into shapes
9. Ductility – ability to be pulled into wires
10. Density - *refer to chapter B2*
Ø Can be classified according to the five groups of materials
1. Plastics
Non-metallic solids
Most are made from petroleum
Strong but light
Poor conductors of heat and electricity
Does not corrode
Can be moulded into shapes
2. Glass
Non-metallic solids
Brittle
Poor conductor of heat and electricity
Does not corrode
Can be moulded into shapes
Transparent
3. Ceramics
Non-metallic solids
Most common ceramics are made of clay
Brittle and hard
High melting point
Poor conductor of heat and electricity
Does not corrode
4. Fibres
Non-metallic solids
Can be spun into threads and woven into fabrics
Able to absorb dyes
5. Metals
Shiny
Good conductors of heat and electricity
Some corrode while others do not corrode
Malleable
Why must we protect our environment?
Ø Some objects we throw away cannot be broken down and often pollute the environment.
Ø The earth has a limited amount of materials. If we are not careful, we might run out of them one day
Ø Help protect the environment with the 3Rs:
1. Reducing – using less. E.g. use 2 sides of a piece of paper. Use your own shopping bags instead of plastic bags shops provide
2. Reusing – to use old things again instead of throwing them away
3. Recycling – to use old things and make them into new ones by melting them and make into new productsChapter C3
Element
Ø A pure substance that cannot be broken down into simpler substances by chemical methods
Ø Classification of elements:
1. Classifying by state:
---11 elements are gases, 2 are liquids and the rest are solids
2. Classifying as metals and non-metals
3. Classification as of the periodic table
---they care classified according to their atomic structures
Atoms
Ø Made up of proton, neutron and electron.
Ø Neutrons are neutral
Ø Protons are positively charged
Ø Electrons are negatively charged
Ø Protons and neutrons make up the nucleus
Ø Nucleus (+) attract electrons(-) by an electrostatic force
Ø no of protons = no of electrons. Thus an atom is electrically neutral
Compounds
Ø 2 or more elements chemically joined together
Ø E.g
1. Water – hydrogen + oxygen
2. Sand – silicon + oxygen
3. Common salt – sodium + chlorine
4. Sugar – carbon + oxygen + hydrogen
Ø Properties of compounds:
1. Different elements in a compound are joined together in a fixed proportion of mass
2. Compounds have different properties from the elements they are made up of
Ø How can it be broken down
1. Heat or electricity
2. Products are either simpler compounds or elements which the compounds are made up of
Mixtures
Ø Consist of 2 or more substances not chemically joined together
1. Mixture of elements e.g. bronze – copper +t tin
2. Mixture of compounds e.g. seawater – salt + water
3. Mixture of elements and compounds e.g. air – mixture of gases
Ø Properties:
1. Substances of mixture can be mixed in any proportion
2. Mixtures have the properties of substances it is made up of
3. When it is formed, no chemical reaction takes place
4. Easily separated by physical methods such as evaporation or distillation
Magnetic attraction:
Ø Used to separate magnetic substances from non-magnetic substances
Filtration:
Ø Used to separate insoluble solid from a liquid
Ø Lab: a piece of filter paper is placed in a filter funnel is used to filter a mixture. The mixture is poured into the filter paper. The filter paper has very small holes which only allows the liquid to pass through., not the larger insoluble particles.
Ø E.g. human nose, filter-feeder whale
Evaporation
Ø Used to separate a dissolved solid from a solution
Distillation
Ø Used to separate a liquid from a solution
Ø Lab: the seawater in the flask is heated until it boils. Porcelain chips are placed in it to keep the pressure of the water low so it would not spill out. The water turns into steam and passes through the condenser. The water vapour is cooled and condenses into water. The salt remains in the distilling flask.
Fractional Distillation
Ø Separate a mixture of 2 or more substances with different boiling points
Chromatography
Ø Separates coloured components of a mixture
Ø Lab: when filter paper is placed in liquid, the liquid moves up the filter paper. When liquid reaches the spot of dye, it dissolves the substances of dye and continue moving up. It works because different substances of the dye move in different rates. The one that move fastest would reach the edge of the filter paper, while the one that moves slowest would only reach the middle of the filter paper first. If the substances in the mixture has different colours, the colours would be more visible as it spreads out. It gives quick results and works with only small amounts of mixture.
Ø To identify colour in dyes
Ø Identify coloured substances used in food products
Ø To help solve crimes. For example, to find out what type of ink is used in forged cheques.
Crystallization
Ø Used to purify solids by dissolving them in a solvent to produce a solution
Ø Lab: the solid is dissolved in a liquid. It is them heated to evaporate most of the solvent. The hot solution is allowed to cool and pure crystals appear upon cooling. To dry the crystals, then cold solution is poured off and the crystals are pressed between 2 filter papers.
Chapter C4- part 1
Solution
– mixture of dissolved solid in a liquid
Soluble
– if a solid is added to a liquid, dissolves and is part of the liquid, the solid is soluble
Insoluble
– substances that do not dissolve in a liquid
Solute
– substance that dissolves in liquid (solid)
Solvent
– liquid used to dissolve other substances (liquid)
Solute + solvent – solution
Properties of solution:
Ø Clear, we are able to see through it
Ø May be coloured or colourless
Ø It is homogenous – every part of the solution has the same properties such as colour and density
Ø If it left to stand, the solute particles do not settle to the bottom
Ø Solute particles can pass through filter paper
Ø Particles of the solute separate and mix evenly with solvent particles
Suspension
– mixture that the solid does not dissolve but remains suspended in the solvent
E.g. muddy water, blood, orange juice, milk
Properties of suspension:
Ø Cloudy, we are unable to see through it
Ø It is heterogeneous – appearance is not the same in every part
Ø If it is left to stand, the solid particles settle to the bottom
Ø Solid particles cannot pass through filter paper
Factors affecting solubility
Ø Type of solute
– different solids have different degrees of solubility in a solvent. Some solids are more soluble than others
Ø Type of solvent
– some substances may be more soluble in one solvent that another
Ø Temperature of solvent – as the temperature of water increases, most solids become more soluble in it
Factors affecting rate at which solid dissolve in the solvent
Ø Temperature
– most solids dissolve faster at higher temperatures
Ø Surface area
– smaller pieces of solid dissolve faster than large pieces because the small pieces have a larger surface area contact with the solvent
Ø Stirring
– solids dissolve faster when the solution is stirred
i havent done on acids and alkali yet.
and havent done physics.
will do it soon
but not so soon (:
must mug finish acids and alkali
then mug history
then do my 4 newspaper articles
then do art
woohooo
love,
crystal :D
