EL
ee
ffi
ff
ffi
i
ffi
g
© lb i © © ti i w © §
ENffifflERE
giv Understand
that matter is
Matter is anything that ®©®anpei©s sBDae© ancl has mass.
made up of tiny
discreet particles
in constant and
random motion
P Understand the
concept of the
particulate model
of matter
All living things and non-living things are matteFT.
fy Usethe
particulate
model of matter
to explain
the physical
properties and
phenomena
of matter in
everyday life
fty Explain the
processes of
melting and
hailing in matter
Pifeysi©al sttatt© Off maaffEL©ff
®
Matter can existeither as asolid9 a liquid or agas at room temperature.
®
The physical state of matter at room temperature clepencls on its m©lEineg
pe®irmE ancl ife®iiirmg pe®irmE.
®
M©Ittirmg pe®irmft is the point of temperature at which a substance changes
from a solicl into a liquicl.
®
EB®ilirmg IT®inefl is the point of temperature at which a substance changes
from a liquid into a gas.
The physical state of a substance at room temperature:
-A s®Iidi if its m©lEirmg BD®irmt i§ higheFT tharm the room temperature
-A iiqenidi if its rm©iEiifeg p®iifett is l®w©FT Eifeam the room temperature
-A gas if its le©iling ffi®iBflt is I®w©FT than the room temperature
The physical properties of solicls, Iiquicls ancl gases are as follows:
®
The mass of a substance is e®mservedi when it unciergoes changes in
its physical state.
© wis®REaREffi pREPeBEsifeiffi8
ffl 3ffi
©ifefflffis®ff © "© Penrtti6ngleBti© RE®di©l Off Mentitleff
®BBaffig® im HBELysi®al sttatt®
®
Achange in physical state cioes not procluce newsubstances. It is called
a #ysi®al ©ELaarmg© only.
®
Heat is tak©rm ira ffB®©m tth© sELflffff®ELflrmdiirmgs when substances unclergo
melting ancl boiling/evaporation.
®
Heat is giv©m ®outt tt® Eife© suFTFT®ELflnediiifegs when substances unclergo
freezing ancl conc]ensation.
•'
'
,I._ ..., L'
,,
'
'
,I.`,i ,,-.. '!.,¥ -,,..
ineat is givere Out E® Eifee suFFT®urediiregs
E%fiMPLE
Diagram A below shows two balloons, % and ¥, being balanced on a plastic rod®
Both balloons are filled with the same amount of air initially.
Diagram A
Diagram B
When the air Of balloon % is allowed to escape, the rod starts to tilt to one side. The
two balloons are not balanced anymore as shown in diagram 8.
(a)
Explain the observation in diagram B.
(b)
!s air a matter? Explain your answer.
§®EREEE®ffi
(a)
When the air of balloon x starts to escape, the mass decreases. It becomes lighter than
balloon Y as balloon Y still contains the same amount of air inside it.
(b)
Airis a matterbecause ithas mass.
© Wfis©REffiREife PREife85sife5neg
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
fl 35
RARTI€LES IN MATTER
•
•
•
Matter is made up of tiny discreet particles.
These tiny discreet particles are in constant and random motion.
Diffusion of substances is a common evidence to demonstrate that
matter is made up of particles which have constant and random motion.
Diffusion in liquid*
Diffusion of copper(lI) sulfate crystals in wtlter
•
ln an experiment, some blue copper(ll) sulfate crystals are added to the
water in a beaker.
water
blue colour of copper(lI)
sulfate crystals starts to
spread in water
copper(I I) sulfate crystals
After a period of time, copper(lI) sulfate crystals start to diffuse which can
be observecl by the spreading of blue colour in water.
blue colour of copper(ll)
sulfate crystals spreads
evenly in water
This experiment shows that copper(ll) sulfate crystals consist of tiny
discreet particles which have constant and random motion in water.
Diffusion in gas*
Diffusion of bromine gqs
•
Brownish bromine gas can be used to demonstrate the constant and
random motion of particles in gas.
In an experiment, a gas jar containing air is placed on top of another jar
with bromine gas.
The contents of these two jars are separated by a lid initially.
After the lid is removed, they are left undisturbed for a period of time.
In the end of the experiment, both jars fill with bromine gas.
© WiseMafifl Publ5shimg
136
SifeREffifl©gr © "® P6Egrtii6eB16BBe EN®di®I Off M6aBt®ff
The c!iagram below shows the set up of this experiment to illustrate
diffusion process in gas.
I-*I
bromine gas
diffuses
upwards
bromine gas
-`-..'
,`t
bromine mix€
completely in
both jars
`
afteFT a few
ife®urs
HELE PAREH16usELffiHE RE®BEEL 0F MffiFTHER
®
®
®
Since matter is macle up of particles, it is important to know how these
particles are arrangecl and behave in it.
At room temperature, matter exists as asolicl, a liquid or agas.
The particles in a matter are arrangecl ancl behave clifferently in different
physical states.
USING "E PARTICULATE MODEL 0F MATTER T0 EXPLAIN PHYSICAL
PROPER"ES 0F MAHER
•
The physical properties of matter can be explained by using one of the
factors in the particulate model of matter:
- Motion of the particles
-Attractive force between the particles
-Arrangement of the particles
- Distance (or space) between the particles
© WiscREaenm PuE885sfiiitg
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
1 37
EXAMPLE
Use the particulate model of matter to explain the following phenomena.
(a}
{b)
The volume increases when 100 cm3 of water evaporates.
Ethanol has a boiling point of 78°C but sodium chloride crystals have a boiling
point Of 1465°C. Explain why ethanol has a lower boiling point than sodium
chloride crystals.
SoiHEi®H
ffl3®
(a)
When water evaporates, it changes its physical state from liquid to gas. The particles in
gaseous state can move freely in all directionsr occupying more Spaces than when they
are in liquid state® Therefore, the volume increases when water evaporates.
{b}
The attractive forces between the ethanol particles are weaker than those in between
the sodium chloride particles, so lesser energy is required to break the forces of attraction between the ethanol particles. As a result, the boiling point of ethanol is lower than
sodium chloride crystals,
© Wis@REaunne PapieBisifeimg
©ifefflffiE©er © The Porticulute Model of Matter
Spaces between particles in matter
®
In the particulate model of matter, the arrangement of particles in solic!s,
liquids and gases is different.
The space between the particles in solid is lesser because the particles
are closely packed together.
The space between the particles in liquids and in gases are greater than
in solids because their particles are arranged in clisorderly manner.
When a substance made up of smaller particles is mixed with another
substance with larger particles, the smaller particles will occupy the
spaces between the larger particles.
larger particle
smaller particles fill in the spaces
between the larger particles
smaller particle
Example
An experiment to demonstrate the existing of spaces between particles
in matter
liquid A
liquid B
mixture of
liquids A and 8
-5o.ocm3=-
®ieservati®re
When 50.0 cm3 liquid A is mixec! with 50.0 cm3 liquic! 8, the total volume
of the mixture is less than 100.0 cm3.
IneferenGe
1.
The size of the particles in liquic! A ancl in liquid a are different.
2.
The particles with smaller size fill in the spaces between larger
particles. As a result, the total volume of the mixture is less than the
expected volume.
© wi§©REffiffiRE pREifeEa§ifeBffi8
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
1 3©
§E6H[®EN A: MELjELEipELE-©EL©lcE ®usES"®ENS
1.
Which of the following properties is true for both solids anc! Iiquicls?
A.
C.
Both have fixed shapes.
Both have the same ciensities.
a. Both have fixed volumes.
D. Both have the same colour.
What happens to the particles in a balloon when it is compressec!?
A. The particles move slower.
8. The particles move freely, bounce ancl knock against each other more often.
C. The particles vibrate more vigorously about their fixed positions.
D. The particles can`not move at all.
Which event would take place when steam changes back to water at room temperature?
A.
8.
C.
D.
4.
The particles become regularly arrangecl.
The particles become smaller.
The particles lose energy ancl move slower.
The particles move further apart.
Which of the following statements best explains why gases clo not have fixecl shapes?
A.
Their particles vibrate at their fixecl positions.
a. Their particles move about within confined space.
C® Their particles have very strong attractive force between them.
D.
5.
Which of the following examples does not have mass?
A. Steam
a. Vacuum
C.
6.
Their particles travel randomly in all c!irections.
Air
D. Mercury
Which statement is true about table salt crystals when they change to liquid after
melting?
A.
a.
C.
D.
7.
140
Itdoes notoccupyspace.
Itdoes nottake the shape of its container.
Itdoes not have adefinitevolume.
It cannot be compressed easily.
Which of the following examples is/are not matter?
11.
Shadow
I.
Light
Ill.
Heatenergy
A.
I,11
a.I,lil
C.
11,Ill
D.
I,11,Ill
© WEseREamn Publishing
€ifeaeifE©er © The Pqrti€ultlte Model of Mqtter
8.
The diagrams below show the change of physical states of a substance after strong
heating.
Afterstrongheating
©
©
_©©
RERERE
Which of the following statements is not correct about the diagrams shown above?
A. After strong heating, the substance takes the shape of a container.
a. The change of physical states involves heat energy being absorbed in the process.
C. The compressibility of the substance increases after strong heating.
D. The mass of the substance remains the same after strong heating.
9.
Which characteristic is not similar between the flowering plants and animals?
A. Both require oxygen to obtain energy in order to carry crucial chemical activities.
a. Both are made up of small discreet particles.
C. Both release oxygen for certain chemical processes as by-product.
D.
Both have masses and occupy space.
10. Which of the following descriptions can be applied to a sheet of paper?
I.
Ithas massand occupiesspace.
11.
111.
IV.
11.
It has lowcompressibility.
Itdoes not have adefinite shape.
It has adefinite volume.
The diagram below shows a balloon filled with helium gas.
in
helium gas
When it is released, it rises up in the air. Which of the following statements is not
correct?
A.
The balloon is filled with an elementonly.
a.
The density of helium gas is lower than the density of air.
Helium gas particles cannot move randomly in all directions inside the balloon.
The attractive force between helium gas particles in the balloon is negligible.
C.
D.
© WiseManfi Pub!ish5fig
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
1 41
Questions 12 ancl 13 refer to the following.
In an experiment, a stuc!ent mixes two liquic!s, X ancl Y of 40 cm3 each, as shown below.
liquid x
mixture of X and Y
liquid Y
79.0 cm3
fiidHfiidHife>
40.0 cm3
Assume that there is no loss in any liquicl, the studem observes that the total volume of the
mixture is less than the expectecl value.
12. What coulcl be the objective of this experimem in term of the particulate moc!el of
matter?
A.
8.
C.
D.
13.
To show the presence of attractive force of particles in liquicls
To showthe presence of space between particles in liquids
To showthe arrangement of particles in liquicls
To showthe motion of particles in liquicls
Which of the following is the clependent variable in this expeFTiment?
A.
Typeof liquicls
8.
Size of measuring cylinders
C.
Initial volume of each liquicl usec!
D.
Total volume of the mixture
14. Which of the following examples cloes ma©t illustrates the c"ffusion of a substance?
A.
Water in a glass turns recl when a drop of red ink is ac!c]ec! to ite
8. An ice culee changes into water when it is left on a ieench at room temperature.
C® The air in a shopping centre is permeated with perfumery fragrance.
D. The smoke from leuming of garbage rises in the air.
15. A rusty iron bar is placec! on a floor mac!e of marble tiles. After a perioc! of time, some
brownish stains are seen on the tiles which cannot lee removecl. Which statemem leest
explains this observation in term of the particulate model of matter?
A. It shows that the particles of the rusty iron bar c]o not have fixecl arrangement.
Be
C.
lt shows that the particles of the rusty iron bar have weak attractive force between
them.
It shows that particles of the rusty iron bar are alele to cliffuse uncler certain
conditions.
D.
It shows that the particles of the rusty iron bar are alele to move` about freely in all
c!irections.
fl42
© W5s©REauerm PdiifeGEsifeieng
©ifeffiREtt©gr ® "e PeBrti6egl6at® RE®elel ®fi MciEteF
16. An experiment was set up as shown below.
blue colour
copper(ll) sulfate
starts to spread
crystals
After a while, blue colour of the copper(ll) sulfate crystals startec! to spreac! in water.
Which of the fojjowing cannot foe cleducecj from this experjmem?
A.
8.
C.
D.
There are spaces between water particles,
The copper(W) sulfate particles break free from their fixed posjtjons.
The particles of sulestances are in constant ranc!om motion.
The particles of substances in liquic!s c!o not have attractive forces.
i7. Which of the following is not matter?
A.
Light
C.
Air
iB® A flask contains two c!ifferent gases, X and Y. Gas X has a higher density than gas Y.
Which c!iagram best shows the arrangement of particles insicle a container filled with a
mixture of these two gases?
A-
8.
C.
© WBs©REamen PusifeEEsifeiifeg
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
H 43
19. The diagram shows a spoonful sugar crystals dissolved in water.
sugar crystals
Which one of the following correctly describes the particles in a dilute sugar solution at
room temperature?
water molecules
sugar molecules
widely separated and
moving at random
widely separated and
moving at random
close together and vibrate
widely separated and
Only
vibrate only
widely separated and
moving at random
close together and moving
at random
close together and moving
at random
widely separated and
moving at random
20. Which of the following statements is correct?
A. The particles of a substance have lesser kinetic energy in solid state than in liquid
state.
8.
C.
D.
The particles in liquids move freely in all directions when temperature increases.
The size of the particles in gaseous state is bigger than those in liquid state.
The mass of a given sample of substance increases when it changes from solid to
liquid.
144
© WiseREaflfi PubBishifig
©ife6§REtt®ff 9 FBBe PeBrti6eB16ate RE®diel ®f REeatEeF
§E©H[®EN B: SBH©REH ffiENSWERE ®EL]ESHi®ENS
1.
Using the particulate model of matter, explain briefly the following observations.
(a)
Liquid mercury is more difficult to compress than helium gas.
(b)
In an experiment, two gas jars containing different gases are arranged in the
horizontal position as shown below.
alr
bromine gas
after one hour
2.
(i)
Bromine gas fills both gasjars completely after one hour. Explain why it is so.
(ii)
Use the particulate model of matter to explain this observation.
The diagram below shows a beaker containing boiling water.
boiling water
© WiseENamffi PBBPeEisBBimg
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
1 45
(a)
(b)
3.*
Sketch the arrangement of particles for the following.
(i)
boilingwater
(ii)
steam
Describe whatwould happen to the motion and the distance of particles during boiling
in terms of the particulate model of matter.
ln experiments I and 1B, a spoonful of blue dye powcler is placecl in a solidifiec! colourless
gel ancl water respectively.
solidifiedgel
Experiment I
afterafewdays
Ill+
blue dye powder
Experiment 11
water
after a few hours
1111>
blue dye powder
146
© WBs®REamm PenifeH5sifeBeng
€ifeffiifG©gr © The Pqrticulqte Model of Mqtter
lt is observed that blue dye powder takes a shorter time in experiment 11 to turn the water
blue completely.
4.
(a)
Explain why the solidified gel and water turns completely blue in the end of both
experiments.
(b)
Explain, in term of distance between particles of substance, why the content in
experiment I takes a longer time to turn blue completely than in experiment 18.
In an experiment, a glass is invertecl into a beaker of water as shown below.
The water cloes not fill in the glass completely when the glass is invertecl.
(a)
Suggest the possible objective for this experiment.
(b)
(i)
(ii)
Give One physical propertyofwater in the beaker.
Using the knowleclge of the particulate mociel of matter, explain why water has
the physical property in (le)(i).
© wi§©REffiffiffi pREifeiBsffiiffi8
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
fg4F
5.
An experiment is set up leelow to Break down liquicl paraffin soakecl in cotton wool by
stFTong heating.
A gas is collectec! when the first leubleles appearecl. Two test tutoes are usecl to collect two
gases with different boiling points.
(a)
Explain why heating paraffin is a chemical change.
(b)
(i)
(ii)
Hence, clescribe the behaviour of particles in terms of motion anc] distance at
X.
(c)
148
What property enables the gas to be collectecl in water?
© W5s®fienffiREae PusifeB@sifeEueg
€ifeenifG©er © The Pqrticulqte Model of Mqtter
6.
The diagrams show the arrangement of the particles in two substances x and Y.
HREREREREE
substance Y
substance X
Use the ciiagrams to answer the following questions.
(a)
Why do substances X and Y have a low compressibility?
(b)
What is the similar motion in both the particles of substances X ancl Y?
(c)
When a fixecl amount of liquid is added into substance Y, the sum of the volume for
the mixture is lesser than the actual volume. Based on the diagram, explain why it is
SO.
(cl)
Why do substances X ancl Y have a fixecl volume?
© Wis©NIafi!m PenifeflEsifeifflg
Comprehensive Guide LOWER SECONDARY SCIENCEA& B
1 49
sE6Hi©EN ©: FTREEE REEsp©ENSE ®agEs"©ENs
1.
(a)
(b)
Explain why solicl sugar crystals have fixec! shape ancl volume.
(i)
(ii)
2.
15©
Explain why diffusion of substances is possible by using an appropriate
example.
Describe an experiment to clemonstrate the cliffusion of substances®
Describe in cletails, using the knowleclge of the particulate moc!el of matter, the changes
in the particles when water is placecl in the freezer unit of a refrigerator.
© wis©REffiusRE pREifeEGsifeERE9