Form 4 Chemistry KSSM 2.1

1. 2.1 BASIC CONCEPT OF
MATTER
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2. 1) Any substance that has mass and volume is considered matter.
2) Matter can exist in three physical states ; solid, liquid and gas.
3) For example, water exist as ice , liquid and steam.
4) The kinetic theory describes the movement and behaviour of the particles in the form
of solids, liquids and gases.
5) The kinetic theory of matter states that
a) matter consists of tiny discrete particles known as atom,molecule or ion.
b) these particles are in continuous constant motion.
Atom Molecule Ion
• Smallest particle
that take part in a
chemical reaction.
• E.g. sodium(Na) ,
magnesium(Mg) ,
carbon(C) ,
hydrogen (H).
• Consists of two or
more atoms joined
by chemical bonds.
• E.g. oxygen(O2) ,
water (H2O) , and
carbon dioxide
(CO2).
• Positive charge –
cation(atom loses
electron)
• Negative charge –anion
(atom gain electron)
• E.g. sodium ion (Na+) ,
aluminium ion (Al3+) ,
chloride ion (Cl-).
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3. Solid Liquid Gas
Arrangement of
particles
• Closely packed
• Arranged in an
orderly manner
• Further apart
• Not arranged in
an orderly manner
• Very far
• Not arranged
Movement of
particles
Vibrate about the
fixed position
Vibrate, rotate and
move freely around
Vibrate, rotate and
move freely around
at high speed
Attractive force
between particles
Strong Weak Very weak and
almost negligible
Kinetic energy Low Moderately high High
Other properties • Definite shape
• Incompressible
• Fix volume
• Take the shape of
the container
• Slightly
compressible
• Fix volume
• Take shape of
container
• Easily
compressible
• No fix volume
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4. Evidence for the kinetic theory of matter are
diffusion and the changes in the state of
matter.
DIFFUSION
1. Diffusion occurs when particles of one substance move
through the space between particles of another
substance.
2. Diffusion spreads out the particles aver a large area,
3. Gases diffuse very quickly as the particles have a higher
energy and move very fast. There is also more empty space
between the particle to move about.
4. For example, diffusion of bromine gas.
1. Liquids and solid diffuse very slowly as the particle
have lower energy and move slower.
2. For example, potassium manganate(VII) solution
dissolves in water.
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5. Changes in the state of matter.
Inter-conversion of state of matter
1. Matter can change from one
state to another if heat is
absorbed or released from it.
2. The change in temperature will
influences the kinetic energy or
the speed of the motion of the
particles.
3. The kinetic energy of the
particles in a substance is
directly proportional to the
temperature of the substance.
Melting is a process in which solid
changes into liquid upon heating at a
certain temperature.
AB: The temperature increase as heat
energy is absorbed. The particles gain
kinetic energy and vibrate vigorously.
The substance exist in solid state.
BC: The temperature remains constant
as the heat is supplied is absorbed to
overcome the forces of attraction that
hold the particle in their fixed position.
The substance exists in solid and liquid
states. The temperature at which a
solid is converted to a liquid is known
as melting point.
CD: The particles gain more kinetic
energy and move faster as
temperature increase. The substance
exists in liquid state.
Freezing is a process in which liquid
changes to solid upon cooling at a
certain temperature.
RS: The temperature decreases as the heat
energy is released to the surroundings. The
particles lose kinetic energy and move closer
together. The substance exists in liquid state,
ST: The temperature remain constant as the
heat energy released to the surrounding is
balanced by the energy liberated to attract
the particles together. The substance exists in
solid and liquid states. The temperature at
which a liquid is converted to a solid is known
as freezing point.
TU: The particle move slower as they lose heat
energy as temperature decrease. The
substance exists is solid state.STUDENTCORNER45

6. Supercooling only occurs if the
solution is cooled too quickly and
not properly stirred during the
cooling process.
EXERCISE
1) WHICH PROCESS OCCURS WHEN
IODINE CRYSTALS ARE HEATED
AT ROOM TEMPERATURE AND
PRESSURE?
A. MELTING
B. FREEZING
C. EVAPORATION
D. SUBLIMATION
2) TABLE BELOW SHOWS THE
BOILING POINT AND
MELTING POINT OF
SUBSTANCES, V,W,X AND Y.
Fun Facts
Subtances Boiling
point (°C)
Melting
point (°C)
V 268 197
W 170 150
X 130 80
Y 17 8
Which substance is a liquid at 100°C ?
A. V C. X
B. W D.Y
ANS
1)D
2)C
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