vi-chemistry chapter-4 mattermetasofsda.in › ... › uploads › sites › 4 › 2020 › 04 ›...
TRANSCRIPT
VI-CHEMISTRY CHAPTER-4 MATTER
SYLLABUS
MATTER-PROPERTIES OF MATTER-STATES OF MATTER-
CHARACTERISTICS OF SOLID, LIQUID AND GAS-
ARRANGEMENT OF ATOMS/MOLECULES IN SOLID,LIQUID AND
GAS- PHYSICAL PROPERTIES OF MATTER.
TOPICS COVERED
MATTER
INTRODUCTION
PROPERTIES OF MATTER
STATES OF MATTER-SOLID,LIQUID,GAS
CHARACTERISTICS OF SOLID LIQUID AND GAS
ARRANGEMENT OF ATOMS/MOLECULES IN SOLID,
LIQUID, AND GAS
INTERCONVERSION OF STATES OF MATTER
PHYSICAL PROPERTIES OF MATTER
CHEMICAL PROPERTIES OF MATTER
INTRODUCTION
The materials which are found in nature are called naturally
occurring materials. You also have seen objects such as Cup,
mugs, bucket, made up of plastic which is also a material.
It is not found in nature but it is made by man and it is called
man-made material.
MATTER
All things are made up of material. Materials are made up of
matter.
Matter is anything that can be perceived by your senses i.e.
you can see, hear, taste smell or touch matter.
For example: air cannot be seen, but you can feel it.
Matter is defined as - Anything which occupies space and has
mass.
PROPERTIES OF MATTER
Matter has mass and occupies space
Mass-The mass of an object is always the same regardless of
where the object is, an object would have the same mass on
the moon on the Jupiter as it has on earth.
Mass is the quantity of matter in an object, whereas weight is
a measure of Earth's pull of gravity on an object.
For example, if you could travel to Jupiter, you would weigh 2.5
times more on Jupiter than on earth, while your mass remains
the same.
Volume -The space occupied by an object is called its VOLUME
Suppose the length, breadth and height of a block is 4 cm, 3 cm
and 5 cm.
Its volume= Length × Breadth × Height
= 4 cm × 3cm × 5 cm =60 cm
The volume of the block is 60 cubic cm. It means that the space
occupied by the block is 60 cubic cm.
STATES OF MATTER
Matter exists in three physical states such as solid, liquid and
gas.
The following are the features associated with the existence of
matter in different states of matter as:
(a) Arrangement of atoms and molecules
(b) Shape and size
(c) Compressibility
(d) Rigidity
(e) Diffusibility
SOLID
Solid matter is highly rigid so it has definitely shape and definite
volume.
Example: wood, iron, brick, glass, stone.
Characteristics
• Rigidity- It is highly rigid.
• Compressibility- solids are incompressible because its
particles are very closely packed. They can expand or contract
to a small extent when heated or cooled.
• Volume -solid have a definite volume
• Shape- solids have their own shape because their molecules
are very tightly packed and cannot move freely.
• Fluidity - they do not flow.
LIQUID
This State of matter is less rigid and can be compressed i.e. the
shape of a liquid can be changed by compressing it. So a liquid
matter does not have a definite shape, but have a definite
volume.
Examples: water, milk, oil etc.
Characteristics
• Rigidity- it is less rigid compared to solid
• Compressibility- can be compressed to a small extent
because the molecules are quite close together and spaces
between them are more.
• Volume- liquids have definite volume.
• Shape- liquids do not have a definite shape but take the
shape of a container because the molecules are free to move
from one direction to another.
• Fluidity- They have a tendency to flow because its particles
can slip slide or glide due to weak intermolecular force of
attraction.
GASES
This state of matter is least rigid and highly compressible so
gases don't have a definite shape or volume.
Examples: carbon-dioxide, oxygen, hydrogen etc.
Characteristics
• Rigidity- Gases are least rigid among all other States of
matter.
• Compressibility- Gases are highly compressible because there
is lot of empty spaces between molecules of a gas.
• Volume- Gases do not have a fixed volume
• Shape Gases do not have a definite shape but take the shape
of a container because the intermolecular space in gas is
maximum and the intermolecular force of attraction is
negligible. So the molecule move freely all around in a closed
container and fill the entire space
• Fluidity- Gases have maximum fluidity because the molecules
of gases move freely.
Click the link below to have better understanding to the topic
https://youtu.be/MrTxRn9MNW
ARRANGEMENT OF ATOMS/MOLECULES IN SOLID,
LIQUID AND GAS.
• Arrangement in solids-
The molecules in a solid are packed close to each other the
only moment they make are small vibrations about their fix
positions the spaces between the molecules are known as
intermolecular spaces these are almost negligible in solid due
to this the molecules attract each other very strong this force of
attraction known as intermolecular force of attraction holds the
molecule together.
• Arrangement in liquid-
The molecules in liquid can move about a little. They are less
tightly packed then in solids i.e. they have bigger
intermolecular space. The molecules of liquid do not have fixed
position. The intermolecular force of attraction between the
molecules of a liquid is weaker than those in solids.
• Arrangement in gas-
The molecules in gases are far apart from one another they
have huge intermolecular space between them they have
almost no intermolecular force of attraction holding them
together, the molecules collide with each other and move in all
directions.
Click the link below to have better understanding to the topic
https://youtu.be/bwGim-eceS
COMPARISON OF SOLID, LIQUID AND GAS.
1. Intermolecular space- There lies space between the
molecules. The space between the molecule is called
intermolecular space.
2. Intermolecular force of attraction- Molecules are held with
each other by a force called intermolecular force of attraction.
More the intermolecular space less is the force of attraction
and vice versa.
3. Movement of molecules- Molecules in matter keep on
moving about the fixed position. More the intermolecular
space, more is the movement of molecules. More the
intermolecular force of attraction, less is the movement of
molecule
4. Volume- less movement of molecule means definite volume
and vice versa
5. Cohesive force- These are attractive forces between similar
molecules
Example: between water-water molecule.
6. Adhesive force- These are attractive forces between
molecules of different material
Example: water molecule and silica
7. Brownian movement- It is the random movement of
microscopic particles suspended in a liquid or gas, caused by
collisions with molecules of surrounding medium.
Example:
• Diffusing in water the particles swirl in random direction
• Beam of light enters in a dark room
8. Shape- More intermolecular force means a definite shape as
molecules are not free to move apart.
9.Diffusion- Diffusion is the process of mixing substance with
each other on their own more is the intermolecular space more
is the diffusion occurs readily in liquid and gases. The molecules
in gases are father apart then the molecules in liquid and solid
and they have a higher speed therefore diffusion occurs more
rapidly in gases than in liquids.
INTERCONVERSIONS OF STATES OF MATTER
Interconversion of States of matter means to change a matter
from one state to another, this change can be brought about by
changing the temperature or pressure of the matter for
example water can be changed from a solid state (ice) into
liquid state by raising the temperature (by supplying heat from
any source) of the solid. Liquid state of water can be changed
into gaseous state (vapour) by for the raising the temperature
to its boiling point 100°C.
TERMS INVOLVED IN CHANGE OF STATE OF
MATTER
• The process of changing a matter from its solid state into its
liquid state by heating is called melting or fusion.
• The process of changing a liquid matter into its vapour or
gaseous state by heating is called vaporization or evaporation.
• The process of changing of a metal from its gaseous state into
its liquid state on cooling is called condensation or liquefaction
• The temperature at which a gas starts changing into its liquid
state is called condensation point.
• The process of changing a liquid matter into its solid state on
cooling is called freezing or solidification.
• The temperature at which a liquid starts changing into its
solid state is called its freezing point.
• The process of changing a solid directly in to its vapor is called
sublimation.
PHYSICAL PROPERTIES OF MATTER.
Physical properties of a matter are those characteristics which
are observed without changing the identity of the matter they
help to distinguish one kind of matter from another. The
Important physical properties of matter are colour, shape,
odour, taste, solubility, melting and boiling points, thermal and
electrical conductivity.
Examples of physical properties of matter
Shapes solids are crystalline having different geometrical
shapes.
Examples: sugar and common salt.
Some solids are amorphous and do not have a definite shape.
Examples: Talcum, powder, flour etc.
Colour -Different substance have different colour.
Example: Gold is yellow (solid) and Copper is pink red (solid)
Chlorine gas is greenish yellow
Taste- most substance have a characteristic taste.
Example sugar (solid) tastes sweet
Salt (solid) tastes salty
Solubility some substance that dissolve in water they are called
water soluble substance
Example: salt, sugar etc
Some substance does not dissolve in water they are called
water insoluble substance
Examples: sand and sawdust etc
Conductivity certain substances allow heat and electricity to
pass through them. They are called good conductors of heat
and light examples iron, copper, Alluminium etc.
CHEMICAL PROPERTIES OF MATTER
• Chemical properties describe matter based on its ability to
change into new matter with different properties
• It can be identified only when new substance has chemical
and physical properties that are different from original
substance
• A chemical reaction takes place when one or more substance
change to form one or more new substances.
• Substances that undergo a chemical change are called
reactants and new substance resulting from this chemical
change are called products
EFFECTS OF HEAT ON MATTER
When heat is added to a body various things can result
• Expansion
• Increase in temperature
• Change of state
• Chemical change
Expansion
When heat is added to a solid, the particles gain energy and
vibrate more vigorously about their fixed positions forcing each
further apart. As a result, expansion takes place. Similarly, the
particles in a liquid or gas gain energy and are forced further
apart. The degree of expansion depends on a substance
For a given rise in temperature, liquid will expand more than a
solid gases expand enormously on heating, causing a possible
expansion if a gas is in a confined space
INCREASE IN TEMPERATURE
When heat energy is added to a substance this result in an
increase in the kinetic energy of its particle i.e. the particles
move at higher speed. Since the temperature is a measure of
the average kinetic energy and the temperature increases.
CHANGE IN STATE
When a solid change to a liquid or a liquid changes to a gas, the
temperature does not change while the change of state is
taking place. The heat absorbed is being used to separate the
particles and there is no rise in temperature when the change is
Reverse exactly the same amount of heat is released. The heat
energy involved in a change of state is called latent heat.
The latent heat of vaporization is defined as the amount of heat
required to change 1 kilogram of a liquid to its gas(vapour) at
its boiling point
CHEMICAL CHANGE
When a substance is heated ,permanent and irreversible
changes occur in which original substance loses its own
composition and properties
Expansion of solids
Solids have three types of expansion namely, linear superficial
and cubical.
When the length of solid increases on heating, it is called
linear expansion.
When the area of solid increases on heating, it is called
areal or superficial expansion.
When the volume of a solid increases on heating, it is
called cubical expansion.
WORKSHEET
Choose the correct option
1. Which of the following is a man-made material?
(a) Water
(b) Wood
(c) Air
(d) Plastic
2. Which of the following is a matter?
(a) Heat
(b) Shadow
(c) Sunlight
(d) Air
3. Water vapour can be changed into water by the process
of ?
(a) Vaporization
(b) Condensation
(c) Melting
(d) Boiling
4. The intermolecular spaces are minimum in cases of?
(a) Solid
(b) Liquid
(c) Gas
(d) Only water
5. Which of the following solid is crystalline?
(a) Common salt
(b) Flour
(c) Talcum powder
(d) Cement
6. The quantity of matter in a body is called ________
(a) Mass
(b) Volume
(c) Weight
(d) Width
7. Smallest unit of substance which can exist
independently.
(a) Molecule
(b) Atom
(c) Compound
(d) Mixture
8. The change of substance from solid to gas is called
________
(a) Crystallization
(b) Condensation
(c) Evaporation
(d) Sublimation
DEFINE 1. Weight- It is a measure of earth’s pull of gravity on an
object.
2. Boiling point- It is the temperature at which liquid
changes to a gas at atmospheric pressure
3. Molecule- It is the smallest particle in a chemical
element or compound.
ANSWER THE FOLLOWING QUESTION 1. What is matter? Name its three physical states.
Ans- Matter is anything that occupies space and has mass.
Solid, liquid and gas.
2. Is the burning of a candlewick a chemical change? Why?
Ans- Yes, because burning of a candlewick produces water
vapour, carbon and carbon-dioxide which cannot be
reversed.
3. Why do liquid take the shape of containers in which they
are placed but not solid?
Ans-Because molecule in liquids are free to move from
one direction to another whereas the molecule of solid are
tightly packed and cannot move freely.
4. What are the factors responsible for the existence of
matter in different states?
Ans- Arrangement of atoms and molecule, shape and size,
compressibility, rigidity, Diffusibility.
5. What are the different effects of heat?
Ans- Expansion, increase in temperature, change of state,
chemical change.
ANSWERS FOR CHOOSE THE CORRECT OPTION
1. Plastic
2. Air
3. Condensation
4. Solid
5. Common salt
6. Mass
7. Molecule
8. Sublimation