UNIT – I: MATTER: NATURE AND BEHAVIOUR
CHAPTER-1
MATTER IN OUR SURROUNDINGS
Revision Notes
Matter
Physical nature of Matter
• Matter is made up of particles that vary in size, shape and nature. These small particles are called atoms.
• The particles of matter are too small so they cannot be seen by naked eyes or simple microscope.
• Characteristics of particles:
(i) Large number of particles constitute matter.
(ii) Particles of matter are very small in size.
(iii) Particles of matter have spaces between them.
(iv) Particles of matter are continuously in motion.
(v) Particles of matter attract each other.
(vi) The force that exists between the particles is called interparticle force of attraction.
(vii) T
he force of attraction between particles of solid, liquid and gas can be arranged in decreasing order
as: Solid > Liquid > Gas.
• Matter around us exists in three states: solid, liquid and gas.
Solid state:
(i) A
ll solids have definite shape, distinct boundaries and fixed volumes, that is, they have negligible
compressibility.
(ii) Solids have a tendency to maintain their shape when subjected to outside force.
(iii) Solids are rigid.
Liquid state:
(i) Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which
they are kept.
(ii) Liquids flow and change shape, so they are not rigid and are called fluid.
(iii) T
he rate of diffusion of liquid is higher than that of solids. This is due to the fact that in the liquid state,
particles move freely and have greater space between each other as compared to particles in the solid
state.
Gaseous state:
(i) Gases are highly compressible as compared to solids and liquids.
(ii) T
he liquefied petroleum gas (LPG) cylinder that we get in our home for cooking or the oxygen supplied
to hospitals in cylinders is compressed gas.
(iii) In the gaseous state, the particles move around randomly at high speed. Due to this random movement,
the particles hit each other and also to the walls of the container. Pressure of gas is applied on the walls of
the vessel by the irregular moving gas particles.
Interconversion of States of Matter
The phenomenon of change of matter from one state to another and then back to the original state by altering the
conditions like temperature and pressure is called the interconversion states of matter. Matter can change its state.
Water can exist in three states of matter:
(i) Solid, as ice,
(ii) Liquid, as water, and
(iii) Gas, as water vapour.
,2 Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX
The states of matter are inter-convertible. The state of matter can be changed by changing temperature or pressure.
S.I. unit of temperature is Kelvin. T (K) = t (°C) + 273.
Melting Point: The temperature at which solid melts to form liquid at atmospheric pressure is called melting
point. Melting point of ice is 273.16 K (0°C)
The melting point of a solid is an indication of the strength of the force of attraction between its particles.
Boiling Point: The temperature at which a liquid starts boiling at the atmospheric pressure is known as boiling
point. Boiling point of water is 373 K (100° C).
Latent heat of vaporization is the heat energy required to change 1 kg of liquid to gas at atmospheric pressure at
its boiling point. Boiling is a bulk phenomenon.
Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.
Freezing: The process in which liquid changes into solid is known as freezing. For example, freezing of water
(liquid) into ice (solid).
Sublimation: Sublimation is the change of a solid directly into the gaseous state without passing through the
liquid state upon heating and back to the solid state when the temperature is lowered.
Evaporation
• Evaporation takes place only at the surface of the liquid while boiling can take place in all parts of the liquid.
• Evaporation is surface phenomenon. Particles from the surface gain enough energy to overcome the forces of
attraction present in the liquid and change into the vapour state.
• Evaporation is a continuous or ongoing process. Evaporation causes cooling.
• The rate of evaporation is affected by the surface area exposed to atmosphere, temperature, humidity and wind
speed.
• Since evaporation is a surface phenomenon, therefore, it increases with an increase in surface area.
• Evaporation increases with an increase in temperature.
• Evaporation decreases with an increase in humidity.
• Evaporation increases with the increase in wind speed.
Plasma: The state consists of super energetic and super excited particles. These particles are in the form of ionised
gases. The fluorescent tube and neon sign bulb consists of plasma stars. The sun and the stars glow because of the
presence of plasma in them.
Key Words
Matter: Anything that has mass and occupies space is called matter.
Solid: Solid is defined as that form of matter which possesses rigidity, is incompressible and hence has a definite
shape and a definite volume.
Liquid: Liquid is defined as that form of matter which possesses fluidity but is almost incompressible and hence
has a definite volume but no definite shape.
Gas: Gas is defined as that form of matter which possesses fluidity but it is highly compressible and hence has
neither definite shape nor definite volume.
Humidity: The amount of water vapour present in the air.
Density: It is the mass occupied by a solid per unit volume and is obtained by dividing the mass of a particular
solid by the volume occupied.
Fusion: The process in which a solid changes to liquid state by absorbing heat at constant temperature.
Diffusion: The process in which particles of one substance occupy the vacant spaces present in the particles of the
other substance, is called diffusion.
Condensation : The process in which a gas changes into liquid state by giving out heat at constant temperature.
Latent heat: The hidden heat which breaks the force of attraction between the molecules during change of state.
Latent heat of fusion: The amount of heat energy that is needed to convert one kg of a solid into the liquid state
at atmospheric pressure at its melting point is termed as latent heat of fusion.
Boiling point: The temperature at which a liquid starts boiling at the atmospheric pressure is known as boiling point.
Freezing point: The temperature at which a liquid changes to solid by giving out heat at the atmospheric pressure.
Latent heat of vaporization: The amount of heat energy that is needed to convert one kg of a liquid at its boiling
point temperature into its vapour state without any rise in temperature, is termed as latent heat of vaporization.
Melting point: The melting point of a solid may be defined as the temperature at which a solid melts to become
a liquid at the atmospheric pressure.
, Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX 3
Sublimation: Sublimation is the change of a solid directly into the gaseous state without passing through the
liquid state upon heating and back to the solid state when the temperature is lowered.
Evaporation: The phenomenon of change of liquid to the vapour state at any temperature below the boiling point
of the liquid is termed as evaporation.
Transpiration: The process of evaporation of water from the aerial parts of plants especially leaves is called
transpiration.
Freezing: The process of conversion of liquid into solid is known as freezing.
Mnemonics
Concept : Matter has three states – Solid, Liquid, M: Matter
Gas S: Solid
Mnemeonics : Ma Sona Le Gayi L: Liquid
Interpretation : G: Gas
Example 1
Write in brief, an activity to show the particulate When we dissolve salt in water, the particles of salt
nature of matter. List any two characteristics of get into the spaces between particles of water. This
particles of matter. shows the particulate nature of matter.
Solution:
Step I: Activity:
(i) Take a 100 mL beaker.
(ii) Fill half the beaker with water and mark the
level of water.
(iii) Dissolve some salt / sugar with the help of a
glass rod. Step III: Two characteristics of particles of matter
(iv) Observe any change in water level. are:
Step II: Observation: Level of water remains same (i) They are continuously moving.
and salt/sugar, has now spread throughout water. (ii) They attract each other.
CHAPTER-2
NATURE OF MATTER
Revision Notes
Matter can be classified as pure substances or mixtures.
A pure substance may either contain constituent particles of only one kind or of different kinds. A pure substance
has a fixed composition.
Element
An element is a basic form of matter which cannot be broken down into simpler substances by any physical or
chemical means.
Elements can be broadly classified as metals, non-metals and metalloids.
Metals are one category of elements that have lustre. They conduct heat and electricity. They are sonorous. They
are malleable and ductile.
Non-metals do not have lustre, are not sonorous and are bad conductors of heat and electricity.
Metalloids are elements having properties intermediate between those of metals and non-metals.
Compound
A compound is a pure substance composed of two or more elements chemically combined in a fixed proportion.
It can be broken down into simpler substances by chemical or electrochemical methods.
Properties of compounds are different from those of its constituent elements, whereas a mixture shows the
properties of its constituent elements or compounds.
, 4 Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX
Mixtures
A mixture contains two or more elements or compounds which are mixed together in any proportion. From a
mixture, no new compound is formed. A mixture shows the properties of the constituent substances.
Mixtures are classified as homogeneous and heterogeneous mixtures.
Mixtures whose components mix completely with each other to make a uniform composition are called
homogeneous mixtures. For example: Alloy.
A heterogeneous mixture has a non-uniform composition.
Alloys are mixture of two or more metals or a metal and a non-metal and cannot be separated by physical methods.
The ability of a substance to dissolve in another substance is called solubility.
Solution
Homogeneous mixture of two or more substances is called a solution.
Component of a solution present in small quantity is called a solute. Solute particles cannot be separated from the
mixture by filtration.
Component of a solution present in large quantity is called a solvent.
Particles of a solution are smaller than 1 nm in diameter. They cannot be seen by naked eyes.
Particles of solution do not scatter beam of light.
Solution with high solute concentration is called concentrated solution and those with low concentration is called
dilute solution. or
The concentration of a solution is the amount of solute present in a given amount (mass or volume) of solvent
Amount of solute
solution. Concentration of a solution =
Amount of solution
Percentage by mass is one method of expressing concentration of solution.
There are two kinds of heterogeneous mixtures: colloids and suspensions
Colloids
Colloids are mixtures with particle sizes from 1 nm to 100 nm.
The component of colloid present in small amount is called dispersed phase.
The medium in which colloidal particles disperse or suspend themselves is called dispersion medium.
In a colloidal system, particles are always suspended and do not settle down. This constant colliding of the
particles in continuous motion is called Brownian movement.
Scattering of a beam of light when light is passed through a colloidal solution is called the Tyndall effect.
Colloids are classified according to the state (solid, liquid or gas) of the dispersed medium or dispersing medium
and the dispersed phase.
Colloid in which dispersed medium is a liquid and dispersed phase is solid is called as sol.
Colloid in which both dispersed phase and dispersed medium are in liquid state is called as an emulsion.
Colloid in which dispersed phase is either liquid or a solid and dispersed medium is a gas is called as aerosol.
Suspension
A suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended
throughout the bulk of medium. Particles of suspension are visible to naked eye. Suspensions are heterogeneous
mixtures with particles that have a size greater than 1000 nanometers.
The change in which the shape, size, appearance or state of a substance may alter but its chemical composition
remains the same is called a physical change. In a physical change, no new substance is formed.
Any change that involves the formation of a new substance and leads to a transformation of chemical identity is
called chemical change.
Chemical changes are usually accompanied with heat exchange. Chemical changes are permanent changes which
are usually irreversible.
Key Words
Matter: Anything that has mass and occupies space is called matter.
Pure substances: It consists of particles of only one kind of matter which are similar to one another and which
cannot be separated into other kinds of matter by any physical process.
Element: It is defined as a basic form of matter which cannot be broken down into simpler substances by any
chemical method.
Metals: They possess lustre. They are malleable and ductile, good conductors of heat and electricity and are
sonorous.
Non-metals: They are neither malleable nor ductile. They are not lustrous and non-conductors of heat and
electricity.
CHAPTER-1
MATTER IN OUR SURROUNDINGS
Revision Notes
Matter
Physical nature of Matter
• Matter is made up of particles that vary in size, shape and nature. These small particles are called atoms.
• The particles of matter are too small so they cannot be seen by naked eyes or simple microscope.
• Characteristics of particles:
(i) Large number of particles constitute matter.
(ii) Particles of matter are very small in size.
(iii) Particles of matter have spaces between them.
(iv) Particles of matter are continuously in motion.
(v) Particles of matter attract each other.
(vi) The force that exists between the particles is called interparticle force of attraction.
(vii) T
he force of attraction between particles of solid, liquid and gas can be arranged in decreasing order
as: Solid > Liquid > Gas.
• Matter around us exists in three states: solid, liquid and gas.
Solid state:
(i) A
ll solids have definite shape, distinct boundaries and fixed volumes, that is, they have negligible
compressibility.
(ii) Solids have a tendency to maintain their shape when subjected to outside force.
(iii) Solids are rigid.
Liquid state:
(i) Liquids have no fixed shape but have a fixed volume. They take up the shape of the container in which
they are kept.
(ii) Liquids flow and change shape, so they are not rigid and are called fluid.
(iii) T
he rate of diffusion of liquid is higher than that of solids. This is due to the fact that in the liquid state,
particles move freely and have greater space between each other as compared to particles in the solid
state.
Gaseous state:
(i) Gases are highly compressible as compared to solids and liquids.
(ii) T
he liquefied petroleum gas (LPG) cylinder that we get in our home for cooking or the oxygen supplied
to hospitals in cylinders is compressed gas.
(iii) In the gaseous state, the particles move around randomly at high speed. Due to this random movement,
the particles hit each other and also to the walls of the container. Pressure of gas is applied on the walls of
the vessel by the irregular moving gas particles.
Interconversion of States of Matter
The phenomenon of change of matter from one state to another and then back to the original state by altering the
conditions like temperature and pressure is called the interconversion states of matter. Matter can change its state.
Water can exist in three states of matter:
(i) Solid, as ice,
(ii) Liquid, as water, and
(iii) Gas, as water vapour.
,2 Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX
The states of matter are inter-convertible. The state of matter can be changed by changing temperature or pressure.
S.I. unit of temperature is Kelvin. T (K) = t (°C) + 273.
Melting Point: The temperature at which solid melts to form liquid at atmospheric pressure is called melting
point. Melting point of ice is 273.16 K (0°C)
The melting point of a solid is an indication of the strength of the force of attraction between its particles.
Boiling Point: The temperature at which a liquid starts boiling at the atmospheric pressure is known as boiling
point. Boiling point of water is 373 K (100° C).
Latent heat of vaporization is the heat energy required to change 1 kg of liquid to gas at atmospheric pressure at
its boiling point. Boiling is a bulk phenomenon.
Latent heat of fusion is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.
Freezing: The process in which liquid changes into solid is known as freezing. For example, freezing of water
(liquid) into ice (solid).
Sublimation: Sublimation is the change of a solid directly into the gaseous state without passing through the
liquid state upon heating and back to the solid state when the temperature is lowered.
Evaporation
• Evaporation takes place only at the surface of the liquid while boiling can take place in all parts of the liquid.
• Evaporation is surface phenomenon. Particles from the surface gain enough energy to overcome the forces of
attraction present in the liquid and change into the vapour state.
• Evaporation is a continuous or ongoing process. Evaporation causes cooling.
• The rate of evaporation is affected by the surface area exposed to atmosphere, temperature, humidity and wind
speed.
• Since evaporation is a surface phenomenon, therefore, it increases with an increase in surface area.
• Evaporation increases with an increase in temperature.
• Evaporation decreases with an increase in humidity.
• Evaporation increases with the increase in wind speed.
Plasma: The state consists of super energetic and super excited particles. These particles are in the form of ionised
gases. The fluorescent tube and neon sign bulb consists of plasma stars. The sun and the stars glow because of the
presence of plasma in them.
Key Words
Matter: Anything that has mass and occupies space is called matter.
Solid: Solid is defined as that form of matter which possesses rigidity, is incompressible and hence has a definite
shape and a definite volume.
Liquid: Liquid is defined as that form of matter which possesses fluidity but is almost incompressible and hence
has a definite volume but no definite shape.
Gas: Gas is defined as that form of matter which possesses fluidity but it is highly compressible and hence has
neither definite shape nor definite volume.
Humidity: The amount of water vapour present in the air.
Density: It is the mass occupied by a solid per unit volume and is obtained by dividing the mass of a particular
solid by the volume occupied.
Fusion: The process in which a solid changes to liquid state by absorbing heat at constant temperature.
Diffusion: The process in which particles of one substance occupy the vacant spaces present in the particles of the
other substance, is called diffusion.
Condensation : The process in which a gas changes into liquid state by giving out heat at constant temperature.
Latent heat: The hidden heat which breaks the force of attraction between the molecules during change of state.
Latent heat of fusion: The amount of heat energy that is needed to convert one kg of a solid into the liquid state
at atmospheric pressure at its melting point is termed as latent heat of fusion.
Boiling point: The temperature at which a liquid starts boiling at the atmospheric pressure is known as boiling point.
Freezing point: The temperature at which a liquid changes to solid by giving out heat at the atmospheric pressure.
Latent heat of vaporization: The amount of heat energy that is needed to convert one kg of a liquid at its boiling
point temperature into its vapour state without any rise in temperature, is termed as latent heat of vaporization.
Melting point: The melting point of a solid may be defined as the temperature at which a solid melts to become
a liquid at the atmospheric pressure.
, Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX 3
Sublimation: Sublimation is the change of a solid directly into the gaseous state without passing through the
liquid state upon heating and back to the solid state when the temperature is lowered.
Evaporation: The phenomenon of change of liquid to the vapour state at any temperature below the boiling point
of the liquid is termed as evaporation.
Transpiration: The process of evaporation of water from the aerial parts of plants especially leaves is called
transpiration.
Freezing: The process of conversion of liquid into solid is known as freezing.
Mnemonics
Concept : Matter has three states – Solid, Liquid, M: Matter
Gas S: Solid
Mnemeonics : Ma Sona Le Gayi L: Liquid
Interpretation : G: Gas
Example 1
Write in brief, an activity to show the particulate When we dissolve salt in water, the particles of salt
nature of matter. List any two characteristics of get into the spaces between particles of water. This
particles of matter. shows the particulate nature of matter.
Solution:
Step I: Activity:
(i) Take a 100 mL beaker.
(ii) Fill half the beaker with water and mark the
level of water.
(iii) Dissolve some salt / sugar with the help of a
glass rod. Step III: Two characteristics of particles of matter
(iv) Observe any change in water level. are:
Step II: Observation: Level of water remains same (i) They are continuously moving.
and salt/sugar, has now spread throughout water. (ii) They attract each other.
CHAPTER-2
NATURE OF MATTER
Revision Notes
Matter can be classified as pure substances or mixtures.
A pure substance may either contain constituent particles of only one kind or of different kinds. A pure substance
has a fixed composition.
Element
An element is a basic form of matter which cannot be broken down into simpler substances by any physical or
chemical means.
Elements can be broadly classified as metals, non-metals and metalloids.
Metals are one category of elements that have lustre. They conduct heat and electricity. They are sonorous. They
are malleable and ductile.
Non-metals do not have lustre, are not sonorous and are bad conductors of heat and electricity.
Metalloids are elements having properties intermediate between those of metals and non-metals.
Compound
A compound is a pure substance composed of two or more elements chemically combined in a fixed proportion.
It can be broken down into simpler substances by chemical or electrochemical methods.
Properties of compounds are different from those of its constituent elements, whereas a mixture shows the
properties of its constituent elements or compounds.
, 4 Oswaal CBSE Chapterwise & Topicwise Revision Notes, SCIENCE, Class-IX
Mixtures
A mixture contains two or more elements or compounds which are mixed together in any proportion. From a
mixture, no new compound is formed. A mixture shows the properties of the constituent substances.
Mixtures are classified as homogeneous and heterogeneous mixtures.
Mixtures whose components mix completely with each other to make a uniform composition are called
homogeneous mixtures. For example: Alloy.
A heterogeneous mixture has a non-uniform composition.
Alloys are mixture of two or more metals or a metal and a non-metal and cannot be separated by physical methods.
The ability of a substance to dissolve in another substance is called solubility.
Solution
Homogeneous mixture of two or more substances is called a solution.
Component of a solution present in small quantity is called a solute. Solute particles cannot be separated from the
mixture by filtration.
Component of a solution present in large quantity is called a solvent.
Particles of a solution are smaller than 1 nm in diameter. They cannot be seen by naked eyes.
Particles of solution do not scatter beam of light.
Solution with high solute concentration is called concentrated solution and those with low concentration is called
dilute solution. or
The concentration of a solution is the amount of solute present in a given amount (mass or volume) of solvent
Amount of solute
solution. Concentration of a solution =
Amount of solution
Percentage by mass is one method of expressing concentration of solution.
There are two kinds of heterogeneous mixtures: colloids and suspensions
Colloids
Colloids are mixtures with particle sizes from 1 nm to 100 nm.
The component of colloid present in small amount is called dispersed phase.
The medium in which colloidal particles disperse or suspend themselves is called dispersion medium.
In a colloidal system, particles are always suspended and do not settle down. This constant colliding of the
particles in continuous motion is called Brownian movement.
Scattering of a beam of light when light is passed through a colloidal solution is called the Tyndall effect.
Colloids are classified according to the state (solid, liquid or gas) of the dispersed medium or dispersing medium
and the dispersed phase.
Colloid in which dispersed medium is a liquid and dispersed phase is solid is called as sol.
Colloid in which both dispersed phase and dispersed medium are in liquid state is called as an emulsion.
Colloid in which dispersed phase is either liquid or a solid and dispersed medium is a gas is called as aerosol.
Suspension
A suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended
throughout the bulk of medium. Particles of suspension are visible to naked eye. Suspensions are heterogeneous
mixtures with particles that have a size greater than 1000 nanometers.
The change in which the shape, size, appearance or state of a substance may alter but its chemical composition
remains the same is called a physical change. In a physical change, no new substance is formed.
Any change that involves the formation of a new substance and leads to a transformation of chemical identity is
called chemical change.
Chemical changes are usually accompanied with heat exchange. Chemical changes are permanent changes which
are usually irreversible.
Key Words
Matter: Anything that has mass and occupies space is called matter.
Pure substances: It consists of particles of only one kind of matter which are similar to one another and which
cannot be separated into other kinds of matter by any physical process.
Element: It is defined as a basic form of matter which cannot be broken down into simpler substances by any
chemical method.
Metals: They possess lustre. They are malleable and ductile, good conductors of heat and electricity and are
sonorous.
Non-metals: They are neither malleable nor ductile. They are not lustrous and non-conductors of heat and
electricity.
