PART A—QUESTIONS
Each chapter contains:
 TIPS AND TRICKS
 FORMATIVE ASSESSMENT
 SUMMATIVE ASSESSMENT

CBSE and Other Important Questions

Objective Type Questions

Higher Order Thinking Skills (HOTS) Questions

NCERT Textbook Questions
Matter in Our Surroundings
1
CHAPTER
Tips and Tricks



Physical nature of matter: Matter is a substance
which occupies mass and space. Its presence may
or may not be felt. Air is matter but smell, hate,
love or security which are felt are not matter. Further matter is particulate, i.e., it is not continuous
but made up of tiny particles.
Characteristics of matter: Particles of matter have
space between them. They are constantly moving.
These interact and diffuse into one another. Diffusion decreases from gases to liquids to solids.
States of matter: The particles of matter attract
each other. This attraction is called intermolecular
force of attraction. Depending on the magnitude
of intermolecular forces, a matter may exist as
solid, liquid or a gas. The gap between particles
increases from solid to liquid to gas.
A solid has a definite shape and a definite volume and
is rigid, has boundary, has negligible compressibility.
A liquid has a definite volume but no definite shape,
has boundary but not rigid.
A gas has no shape, no boundary and no fixed volume.
Change of state of matter: A solid on heating
changes into a liquid which changes into gas on
further heating. On cooling, reverse process takes
place. On heating, kinetic energy of particles
increases which is responsible for change of state
of matter.
A-2

Latent heat: At the melting point, temperature
becomes constant, though heat is supplied, till
whole of solid melts. Similarly during heating of
liquid, at the boiling point, temperature remains
constant. These are respectively called latent heat
of fusion and vaporisation.

Sublimation: In some cases, matter changes directly from solid state to gaseous state and vice
versa without changing into liquid state.

Effect of pressure: On increasing pressure,
particles of matter come closer and they move
apart on reducing pressure at a given temperature.
Thus increasing pressure liquifies a gas. Similarly
solid becomes liquid at lower pressures.

Evaporation: Particles of matter are always
moving and at different speeds. (We measure
average speed). In case of liquid, when particles
having higher kinetic energy reach the surface,
break away by the forces of attraction of other
particles and get converted into vapours. This
phenomenon gives rise to cooling of water in
earthenwares. The rate of evaporation increases
with temperature, surface area, speed of wind and
decreases with humidity.
A-3
MATTER IN OUR SURROUNDINGS
Formative Assessment
ORAL QUESTIONS (Conversation Type)
11. What is the phenomenon known when different
substances mix as a result of random motion of
particles.
1. (a) How do you describe so many substances
around us in one word?
12. How does diffusion vary with density of liquid?
(b) Are invisible substances like gases or air
also constitute matter?
13. What is the temperature at which the liquid
and vapour states of a substance coexist?
(c) What about certain feelings like love, hate,
security, smell.
14. Name the two parameters responsible for the
physical state of matter.
(d) Why?
15. What is the phenomenon called when a solid
changes into liquid?
2. (a) Take some matter, it appears continuous.
Do you agree?
(b) Are these tiny particles closely packed?
16. What is that state of matter which does not
acquire the shape of the container?
(c) How do you demonstrate the gap between
particles of matter?
17. What kind of energy is possessed by particles
due to their random motion?
3. (a) What makes the matter to exist in three
states: solid, liquid and gas?
18. Which state of matter is characterized by
definite boundaries?
(b) What is this called?
(c) How does intermolecular force of attraction
responsible for change of state?
4. (a) Water has boiling point of 100ºC but still
wet clothes dry up even at room
temperature? What is this process called?
(b) Explain Evaporation.
(c) How does this happen?
(d) Give an example of evaporation in our daily
life.
ORAL QUESTIONS
1. What is matter?
2. Which of the following is matter?
air, thought, love, smell of perfume.
3. Why is smell of perfume not a matter?
4. What are the three states of matter?
5. One gas mixes with another gas easily. What is
this property called?
6. Which property of matter is responsible for
diffusion?
7. Which state of matter has no surface?
8. Which state of matter is characterised by
definite boundaries?
9. Which states of matter cannot form heaps?
10. Which states of matter assume the shape of the
container?
19. What property of matter is responsible for
aquatic plants/animals survive in water?
20. What is the term used when the vapours of a
substance on cooling gives solid directly?
21. What happens to the system when the material
contained evaporates?
22. Which state of matter has no open surface?
TRUE OR FALSE
1. Diffusion in liquids increases with density.
2. Latent heat of vaporisation depends on the
nature of the liquid.
3. Evaporation of a liquid increases with
temperature of the atmosphere.
4. Evaporation of water increases with humidity
of the atmosphere.
5. Solid carbon dioxide sublimes at room
temperature.
6. The rate of evaporation of a liquid is
independent of its amount.
7. Evaporation of a liquid is a bulk phenomenon.
8. Melting of a wax under hot sun is a bulk
phenomenon.
9. Light is not considered as matter.
10. Smell of perfume is considered as matter.
11. The particles of matter possess potential energy.
A-4
NEW AGE CCE SCIENCE–IX
12. Liquid and gases assume the shape of the
container.
13. Solids, liquids and gases have open surfaces.
14. The rate of diffusion decreases with
temperature.
15. Evaporation is a surface phenomenon.
QUIZ
1. I am invisible but occupy space and also have
mass.
2. I am a state of matter but no definite boundary,
shape and volume can be assigned to me.
3. I am not a part of matter but is influenced when
matter is either heated or compressed.
4. I do not hesitate to record my presence
whenever a solid or liquid changes its state but
is still considered hidden.
5. I am a property of a gas which enables you to
put large amount of a gas in a small cylinder.
6. I am a gas which extinguishes fire but is never
available as liquid.
7. I am a solid but is very flexible in shape and
size.
8. I am a state of matter with no storage problem/
need no container.
9. My presence in atmosphere decreases the rate
of evaporation of water.
10. I am a state of matter containing super-excited
particles of high energy order.
 Down
2. Cordial behaviour between two persons. (4)
4. Heat during change of state. (6)
B.  Across
1. Force between particles of matter. (14)
3. Not state of matter but glows. (4)
PUZZLES
A.  Across
1. State of matter designated as incompressible.
(5)
3. Surface phenomenon resulting in lowering of
temperature. (11)
NOTES
 Down
2. Denote conversion of solid directly into vapours
and vice-versa. (11)
4. Heat during change of state. (6)
A-5
MATTER IN OUR SURROUNDINGS
Assignments
Name: .............................. Class: ........ Section: ........
Roll No.: ........ Grade: ........ Teacher’s sign: ............................
CLASS ASSIGNMENT 1
1. What happens to the system in which the
contained liquid evaporates at room
temperature?
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2. What is sublimation?
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6. What is latent heat of fusion?
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7. Name the term used to denote conversion of
vapour to solid. Give example.
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3. What is the S.I. unit for pressure?
8. Though both boiling water and steam record a
temperature of 100ºC but still steam is said to
have high energy. Comment.
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4. What is matter?
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5. Why does rate of evaporation of a liquid
decreases with increase in humidity?
9. Define melting point.
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10. How is a solid characterised?
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A-6
NEW AGE CCE SCIENCE–IX
Name: ..............................
Class: ........ Section: ........ Roll No.: ........ Grade: ........ Teacher’s sign: ............................
CLASS ASSIGNMENT 2
1. Give one example each of diffusion and
osmosis.
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2. How do evaporation, diffusion and
compression of gases behave in terms of change
of temperature.
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6. Arrange oil, water and sugar in the increasing
order of forces of attraction between their
particles.
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7. What happens to the distance between the
molecules of CNG when the cylinder of CNG
is slowly used up?
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8. Why is the arrangement of particles in solid
state more ordered than in liquid state?
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3. Under what conditions, gases can be liquified?
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4. Which states of matter behave like fluids?
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9. What is the relation between Celsius scale and
Kelvin scale? Which is used as S.I. unit?
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5. Which phenomenon is responsible for cooling
of water kept in an earthen pot?
10. Why does the temperature of a substance
remain constant during its melting point?
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MATTER IN OUR SURROUNDINGS
Name: ..............................
A-7
Class: ........ Section: ........ Roll No.: ........ Grade: ........ Teacher’s sign: ............................
HOME ASSIGNMENT 1
4. What property of butane is utilized when it is
supplied as LPG?
1. Name two parameters which we observe in our
daily life that are not termed as matter. Explain.
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5. What are ‘intermolecular forces’? How are these
related to the three states of matter?
2. Describe an experiment to show that matter is
composed of particles.
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6. How is pressure developed in a container full
of gas?
3. An agarbatti stick does not smell. When it is
lighted, the smell is felt throughout the room.
Explain the phenomenon.
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7. How does rate of diffusion change with (i)
density of liquid and (ii) temperature? Give
examples.
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A-8
NEW AGE CCE SCIENCE–IX
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8. What produces more severe burns, boiling
water or steam? Explain your answer.
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10. How does the boiling point of a liquid vary
with pressure?
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9. Explain how lumps of ice are more effective in
cooling than water at 273 K.
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NOTES
A-9
MATTER IN OUR SURROUNDINGS
Summative Assessment
CBSE AND OTHER IMPORTANT QUESTIONS
A. VERY SHORT ANSWER TYPE (1 Mark)
1. Which of the following substances is most
compressible?
Air, ethyl alcohol, sodium chloride.
2. In which of the following substances you expect
largest intermolecular force of attraction?
Nitrogen, Water, Acetone
3. Arrange the following substances in increasing
order of force of attraction between the particles.
(i) milk
(ii) salt
(iii) oxygen
(NCT 2008)
4. Expand CNG and LPG. (CBSE Exam. 2010)
5. Which state of matter neither has fixed shape
nor definite volume?
6. Which one of the following is categorised as
matter?
force, fat, work
7. Which energy is possessed by particles of matter
due to their random motion?
8. How does the rate of diffusion change with
temperature?
9. The boiling point of ethyl alcohol is 80°C.
Express it in Kelvin scale.
10. Which will have more impact on kinetic energy;
doubling mass or doubling velocity?
(KVS 2008)
11. Which of the two, boiling or evaporation is a
bulk phenomenon?
12. Gases mix easily. Which property of gases
makes it possible?
13. Boiling point of water is 100°C at atmospheric
pressure. Will it increase, decrease or remain
same with increase of pressure.
14. At 0°C, when heat is given to ice, temperature
remains constant till whole of the ice melts.
What is this heat called that disappears?
15. Which of the following has charged particles?
solids, gases, plasma, liquids
16. How does the amount of liquid influence its
evaporation?
17. Name the term used for solid directly formed
from the gas.
(DAV 2008)
18. Define evaporation.
(CBSE Exam. 2010)
19. Why does the smell of hot sizzling food reach
you several metres away but to get the smell
from cold food you have to go close?
(CBSE Exam. 2010)
20. Why does a desert cooler cool better in a hot
dry day?
(CBSE Exam. 2010)
21. What is the term used for change of solid state
to liquid state?
(CBSE Exam. 2010)
22. Write one important characteristic of matter.
(CBSE Exam. 2010)
23. Convert:
(a) 25°C into kelvin scale
(b) 500 K into celsius scale
(KVS 2009)
24. Name the temperature at which solid and liquid
states of matter can coexist.
25. Why is sponge a solid though compressible?
(NCERT Exemplary Problem)
B. SHORT ANSWER TYPE (2 Marks)
1. How will you show that matter is composed of
tiny particles?
(CBSE Exam. 2010)
2. When a bottle of scent is opened in one corner
of a room, it immediately spreads throughout
the room. What property of matter is
responsible for this observation? Explain.
(CBSE Exam. 2010)
3. How will you show that particles of matter have
space between them?
4. Give one similarity and one dissimilarity
between a liquid and a gas.
5. Separate the following substances into two
groups based on intermolecular forces of
attraction.
ice, camphor vapour, salt, plastic, carbon
dioxide and oxygen.
6. Three materials A, B and C are taken separately
in a cane, bottle and a jar. The volume of C
depends on the size of the container but the
shape of both B and C depends on the container.
The volume of A and B is independent of the
kind of container. Explain which of these is a
solid, liquid and gas?
A-10
7. Three states of matter are interchangeable.
Comment.
8. Three substances X, Y and Z melt at 10°C, 45°C
and –10°C respectively. Their boiling points are
100°C, 500°C and 20°C respectively. State the
physical nature of X, Y and Z at room
temperature.
9. Define (i) Latent heat of fusion and (ii) latent
heat of vapourisation.
(CBSE Exam. 2010)
10. How are particles of matter affected with
increasing or reducing pressure on the matter
at a given temperature.
11. Both boiling and evaporation convert a liquid
into vapours. What is the difference between
the two processes?
(CBSE Exam. 2010)
12. How does evaporation cause cooling of a
container having a liquid?
13. How do you account for appearance of water
droplets on the outer surface of ice-cold water
bottle?
14. What is the effect of surface area on
evaporation? Illustrate.
15. Give reasons:
(a) Dry ice is stored under high pressure.
(b) At many places, especially in rural areas,
people often sprinkle water on the ground
in front of their homes during hot summer
evenings.
16. Explain how the following factors affect the rate
of evaporation of a liquid:
(i) temperature of the liquid.
(ii) area of the exposed surface.
(iii) moisture in the surrounding air.
(iv) increase in wind speed. (CBSE Exam. 2010)
17. (a) The melting points of 2 substances A & B
are 280 K and 320 K respectively. Are these
substances liquid at room temperature?
Justify your answer.
(b) Give an example that shows the state of
matter can be changed into another state
by changing the temperature.
(CBSE Exam. 2010)
18. A sample of water under study was found to
boil at 102°C at normal pressure. Is the water
pure? Will this water freeze at 0°C? Comment.
(NCERT Exemplary Problem)
19. (a) Conversion of solid to vapour is called
sublimation. Name the term used to denote
the conversion of vapour to solid.
NEW AGE CCE SCIENCE–IX
(b) Conversion of solid state to liquid state is
called fusion; what is meant by latent heat
of fusion? (NCERT Exemplary Problem)
20. (a) Dry ice is compressed at high pressure.
What happens when pressure is released?
(b) Suggest a method to liquefy atmospheric
gases.
(CBSE Exam. 2010)
C. SHORT ANSWER TYPE (3 Marks)
1. Give an example of (i) a liquid diffusing into a
solid, (ii) solid diffusing into a liquid and (iii)
solid diffusing into a solid.
2. If you try to walk (i) through solid material
spread around you, (ii) through water and (iii)
through air. What do you observe? What
conclusion can you draw?
3. How do you differentiate between solids,
liquids and gases on the basis of their melting
points and boiling points.
4. Of three states of matter, only gases are said to
have no open surface. Explain.
5. (a) Solids have fixed shape. Suggest a solid
which can change its shape.
(b) Solids are incompressible. Suggest a solid
which can be compressed though
temporarily.
(c) Solids are rigid. Suggest a solid which can
be obtained in different shapes.
6. Give reasons:
(a) Naphthalene balls disappear with time
without leaving any solid.
(b) A gas exerts pressure on the walls of the
container.
7. What are the differences between a gas and
plasma? Explain one use of plasma.
8. Why do cotton clothes suit best in summer?
(CBSE Exam. 2010)
9. What is the relation between boiling point and
the intermolecular forces of attraction between
the particles of a liquid. Explain giving
examples of two liquids.
10. Classify the following into osmosis and
diffusion:
(a) Swelling up of a resin on keeping in water.
(b) Spreading of virus on sneezing.
(c) Earthworm dying on coming in contact
with common salt.
(d) Shrinking of grapes kept in thick sugar
syrup.
A-11
MATTER IN OUR SURROUNDINGS
(e) Preserving pickles in salt.
(f) Aquatic animals using oxygen dissolved in
water during respiration.
(NCERT Exemplary Problem)
11. Coconut oil freezes in winter but mustard oil
does not do so at atmospheric pressure. What
could be state of these liquids at reduced
pressure?
12. A glass beaker containing water as ice kept in
a refrigerator (< 0°C) is removed and kept in
the open. If you could measure the temperature
of the contents of the beaker, which of the
following graphs would correctly represent the
change in temperature as a function of time.
Explain.
14. Give reasons:
(a) Steam produces more severe burns than
boiling water.
(b) We are able to sip hot tea faster from a
saucer rather than from a cup.
(c) Water kept in an earthen pot becomes cool
during summer.
(CBSE Exam. 2010)
15. Answer the following questions:
(i) Arrange the following substances in
increasing order of force of attraction
between the particles.
(i) water
(ii) hydrogen
(iii) sand
(ii) Why does the temperature remain constant
at the melting point?
(iii) Which property of gases makes it possible
to fill large volume of gases in small
cylinders?
(CBSE Exam. 2010)
16. You want to wear your favourite shirt to a party
but the problem is that it is still wet after a
wash. What steps would you take to dry it fast?
(NCERT Exemplary Problem)
17. Why does the temperature of a substance
remain constant during its m.pt. or boiling
point?
(NCERT Exemplary Problem)
D. LONG ANSWER TYPE (5 Marks)
(NCERT Exemplary Problem)
13. Answer the following questions:
(a) Why is ice at 273 K more effective in cooling
than water at the same temperature?
(b) Name the two gases which are supplied in
compressed form in homes and hospitals.
(c) What is dry ice?
(CBSE Exam. 2010)
1. Differentiate between properties of three states
of matter.
2. Discuss the factors which affect evaporation.
3. Why does the temperature of a substance
remain constant during melting? What is the
difference between latent heat of fusion and
latent heat of solidification?
OBJECTIVE TYPE QUESTIONS
FILL IN THE BLANKS
(i) A material in gaseous state can fill any ...............
(ii) The intermixing of particles of two substances
on their own is known as ...............
(iii) The energy possessed by a particles by virtue
of its motion is called ...............
(iv) The ............... point of a solid is an indication of
the strength of intermolecular forces.
(v) The arrangement of particles in ............... state
is less ordered than in ............... state.
(vi) Evaporation is a ............... phenomenon.
(vii) When ice melts, there is a ............... in volume.
(viii) .......... is the change of gaseous state directly
into solid state without going to the ........... state.
(ix) Evaporation of a liquid at room temperature
leads to a ............... effect.
(x) The state of matter can be changed by changing
............... or ...............
A-12
NEW AGE CCE SCIENCE–IX
MULTIPLE CHOICE QUESTIONS
1. Liquids have
(a) fixed volume and fixed shape
(b) fixed volume and no fixed shape
(c) fixed shape and no fixed volume
(d) neither fixed volume nor fixed shape.
2. Materials existing as liquids have
(a) boiling point and melting point above room
temperature
(b) boiling point and melting point below room
temperature
(c) boiling point above room temperature and
melting point below room temperature
(d) both (a) and (c)
3. Which of the following pairs will not exhibit
diffusion?
(a) hydrogen-nitrogen (b) sand-sulphur
(c) salt-water
(d) oxygen-water
4. The fluorescent tubes and neon sign bulbs glow
because of
(a) presence of charged particles
(b) high voltage
(c) high temperature
(d) high density of gases
5. The boiling points of acetone, ethyl alcohol and
butyl alcohol are 56°C, 80°C and 118°C
respectively. Which sequence represents
correctly their boiling points in Kelvin scale?
(a) 353 K, 392 K, 352 K
(b) 392 K, 329 K, 353 K
(c) 329 K, 353 K, 391 K
(d) 391 K, 353 K, 329 K
6. Which of the following processes does not
convert a liquid into vapours?
(a) boiling
(b) heating
(c) evaporation
(d) condensation
7. Which of the following decreases the rate of
evaporation?
(a) surface area
(b) humidity
(d) wind
(c) temperature
8. Diffusion of a liquid in another liquid decreases
with density of the liquids because intermolecular interaction increases.
(a) Assertion is correct and reason is wrong
(b) Assertion is correct and reason is correct
(c) Assertion is wrong and reason is correct
(d) Assertion is wrong and reason is wrong
9. Gases can be easily compressed because these
have least intermolecular interactions.
(a) Assertion is correct and reason is correct
(b) Assertion is correct and reason is wrong
(c) Assertion is wrong and reason is correct
(d) Assertion is wrong and reason is wrong
10. Which of the following processes demonstrate
diffusion?
(i) Spreading of cooked food throughout the
house
(ii) Oxygen dissolved in sea water
(iii) Swelling of egg kept in water
(iv) Drying of wet clothes
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iv)
(d) (i) and (iv)
11. Oxygen gas is contained in a closed cylinder.
Which of the following processes would
increase the intermolecular force of attraction
between oxygen molecules?
(i) Adding more oxygen in the cylinder
(ii) Increase the volume of the cylinder
(iii) Increase pressure on the gas
(iv) Making a small hole in the cylinder.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (i) and (iv)
12. Give the correct choice for the following
process.
Solid state
A
B
Liquid state
C
D
Gaseous state
(a) A is fusion and C is condensation
(b) A is solidification and C is vaporisation
(c) B is solidification and C is vaporisation
(d) A is fusion and D is vaporisation
13. Gases are liquified under
(a) high pressure, high temperature
(b) high pressure, low temperature
(c) low pressure, low temperature
(d) low pressure, low temperature
14. When we add sugar in water, particles of sugar
disappear because they
(i) are very small
(ii) get into spaces between water molecules
(iii) are colourless
(iv) are moving at high speed
(a) (i), (ii) and (iii) (b) (ii), (iii) and (iv)
(c) (i) and (iii)
(d) (i), (iii) and (iv)
A-13
MATTER IN OUR SURROUNDINGS
15. The evaporation of water will decrease
(a) by increase in temperature of water
(b) by increase in surface area of water
(c) by adding common salt to water
(d) by blowing a fan over water.
16. The evaporation process is represented by


(a) solid 
 water
(b) liquid  vapour
(c) solid  vapours
(d) solid  liquid  vapour
17. Gases do not have
(a) high compressibility
(b) high fluidity
(c) high density
(d) high volume
18. Choose the correct temperature-time graph
when steam is slowly cooled.
MATCH THE COLUMNS
1. Column A
(i) density
(ii) pressure
(iii) inter mixing
of liquids
Column B
(a) melting point
(b) rigidity
(c) diffusion
 liquid
(iv) solid 
(v) solids
2. Column A
(i) high compressibility
(ii) diffusion
(d) Pascal
(e) kg m–3
Column B
(a) 233 K
(b) disappearance
of naphthalene balls
(iii) sublimation
(c) gases
(iv) force per unit area (d) pressure
(v) – 40°C
(e) increases with
temperature
NCERT TEXTBOOK QUESTIONS
INTEXT QUESTIONS
Page 3
1. Which of the following are matter?
Chair, air, love, smell, hate, almonds, thought, cold,
cold drink, smell of perfume.
2. Give reasons for the following observation:
The smell of hot sizzling food reaches you
several metres away, but to get the smell from
cold food you have to go close.
3. A diver is able to cut through water in a
swimming pool. Which property of matter does
this observation show?
4. What are the characteristics of the particles of
matter?
Page 6
1. The mass per unit volume of a substance is
called density (density = mass/volume).
Arrange the following in order of increasing
density—air, exhaust from chimneys, honey,
water, chalk, cotton and iron.
2. (a) Tabulate the differences in the
characteristics of states of matter.
(b) Comment upon the following:
rigidity, compressibility, fluidity, filling a gas
container, shape, kinetic energy and density.
3. Give reasons:
(a) A gas fills completely the vessel in which it
is kept.
(b) A gas exerts pressure on the walls of the
container.
A-14
NEW AGE CCE SCIENCE–IX
(c) A wooden table should be called a solid.
(d) We can easily move our hand in air but to
do the same through a solid block of wood
we need a karate expert.
4. Liquids generally have lower density as
compared to solids. But you must have
observed that ice floats on water. Find out why?
Page 9
1. Convert the following temperature to Celsius
scale:
(a) 300 K
(b) 573 K .
2. What is the physical state of water at:
(a) 250°C
(b) 100°C
3. For any substance, why does the temperature
remain constant during the change of state?
4. Suggest a method to liquefy atmospheric gases.
Page 10
1. Why does a desert cooler cool better on a hot
dry day?
2. How does the water kept in an earthen pot
(matka) become cool during summer?
3. Why does our palm feel cold when we put some
acetone or petrol or perfume on it?
4. Why are we able to sip hot tea or milk faster
from a saucer rather than a cup?
5. What type of clothes should we wear in
summer?
EXERCISES (Pages 12–13)
1. Convert the following temperatures to the
Celsius scale.
(a) 293 K
(b) 470 K.
2. Convert the following temperatures to Kelvin
scale.
(a) 25°C
(b) 373°C.
3. Give reason for the following observations.
(a) Naphthalene balls disappear with time
without leaving any solid.
(b) We can get the smell of perfume sitting
several metres away.
4. Arrange the following substances in increasing
order of forces of attraction between the
particles—water, sugar, oxygen.
5. What is the physical state of water at:
(a) 25°C
(b) 0°C
(c) 100°C
6. Give two reasons to justify:
(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room
temperature.
7. Why is ice at 273 K more effective in cooling
than water at the same temperature?
8. What produces more severe burns, boiling
water or steam?
9. Name A, B, C, D, E and F in the following
diagram showing change in its state: