Class 9 science chapter 1 notes
Matter in our surroundings
In this chapter you will learn about what is matter States of matter their properties and much more.
So let's get started 🌟
Important points
- Matter.
- Matter classification
- Particles of matter.
- Characteristics of particles of matter.
- Classification of matter as Solids, Liquids, Gases.
- The common unit of Temperature and SI unit of Temperature
- Change of State of Matter.
- Latent Heat.
- Evaporation.
What is Matter ?
Anything which occupies space and has mass and feel by our sense organ is called matter.
For example: Table, chair, pen, pencil, petrol, kerosene etc.
What is Non-Matter ?
Anything that has no mass and not occupy space is called Non-Matter .
To example: Love, hate, friendship, cold, hotness, thought, idea , sadness etc.
Classification of matter
Matter are classify on the two basis
- On the basis of Physical properties.
- On the basis of Chemical properties.
On the basis of Physical properties Matter are classified as .
- Solid
- Liquid
- Gas
On the basis of Chemical properties Matter are classified as.
- Elements
- Compounds
- Mixture
Matter is made up of particles
Every Matter is made up of tiny pieces of Particles.
The particles which make matter are atom and molecules.
Evidence of Particles of Matter
By Brownian Motion and Diffusion we can get the evidence of matter is made Of particles.
Characteristics of Particles of Matter
- The particles of Matter are very very small.
- The particles of Matter have space between .
- The particles of Matter are constantly moving.
- The particles of Matter attract each other.
Classification of Matter as Solids, Liquids, Gases.
On the basis of physical properties of Matter. There are three States of Matter
- Solid
- Liquid
- Gas
- Plasma
- Bose-einstein condenstate
Solid
A solid is a state of Matter characterised by particles arranged such that shape and volume are relatively stable.
For example: Table, wall, brick etc.
Liquid
A liquid is a nearly incompressible fluid that confirm change in the shape
but retain the volume of container .
For example: Juice, petrol, kerosene etc.
Gas
A gas is compressible and confirms the shape of the container in which it is kept and acquires a uniform density inside a container , even in the gravity and regardless of the amount of substance in the container.
For example: Air, oxygen, Helium etc.
Plasma
Plasma is define as a state of Matter predominantely compressed of ions and electrons . Plasma state is obtain by heating a gas to a seating temperature.
For example: Sun, Lighting etc.
Bose-einstein condestate
It is that state of Matter which forms when a gas of Bosons at low densities is cooler to temperature absolute to zero.
Properties of solid
- Have fixed shape & fixed volume.
- Solids have very less intermolecular space.
- Solids have very high intermolecular force of attraction.
- Have high density.
- Solids are rigid.
Properties of liquid
- Do not have fixed shape but have fixed volume.
- Liquid have more intermolecular space as compared to solids.
- liquids have less intermolecular force of attraction as to solid.
- Have low density as campared to solids.
- Liquids have the the property of mobility.
- Gas neither have fixed shape not fixed volume.
- Gas have more intermolecular space as compared to solid and liquid.
- Gases have least intermolecular force of attraction.
- Have least density.
- Gases are mobile in nature.
The common and SI unit of Temperature.
The common unit of Temperature is degree Celsius.
And the SI unit of Temperature is Kelvin.
the melting point of ice on the Celsius scale is zero degree Celsius and the Kelvin scale is 273
Kelvin. This means that a temperature of 0°on Celsius scale is equal to the 273 on the Kelvin scale so 0°celsius is equals to 273 Kelvin.
Temperature of Kelvin scale = Temperature on Celsius scale +273
Change of State
- By changing the temperature
- By changing the pressure
By changing temperature states of matter will change there state .
Solid to Liquid : Melting
The process in which a solid substance changes a liquid on heating is called melting.
When solid is heated , it changes its state from solid to Liquid.
Liquid to Gas : Boiling ( vapourisation )
The process through which liquid can changes into gas on heating is called boiling.
When we heat liquid it will change its state from liquid to Gas.
Gas to liquid : Condensation
The process of converting gas into liquid by cooling is called condensation.
When we cool vapour it will change into liquid.
Liquid to Solid : Freezing
The process of converting liquid into solid by cooling is called Freezing .
When we cool the liquid it change into solid (ice )
Solid to Gas : Sublimation
The process of converting solid directly into Gas on heating and of vapour into solid on cooling is known as Sublimation.
Sublimation is applicable for some matters like Ammonium chloride, Iodine, Camphor, Naphthalene and Anthracane.
Latent heat
The word latent means 'hidden'.
The heat required to change the state of the substance without increasing its temperature is called Latent Heat.
Latent heat are of two types
- Latent heat of Fusion ( change solid to liquid )
- Latent heat of Vapourisation ( change liquid to Gas )
Latent heat of Fusion
Latent Heat of Fusion is the quantity of heat ( in joule ) 1 kilogram of solid ( as its melting point ) to Liquid without any change in temperature is called latent heat of Fusion .
The latent heat of Fusion of ice is 3.34×10⁵ joules per kilogram ( 3.34×10 j/kg).
Latent heat of Vapourisation
Latent heat of Vapourisation of a liquid is the quantity of heat ( in joule ) required to convert liquid ( as its boiling point ) to Gas without any change in temperature is called Latent heat of Vapourisation.
The Latent heat of Vapourisation of water is 2.25×10⁵ joules per kilogram ( 2.25 j/ kg ) .
Evaporation
The process of a liquid changing into Gas or vapour even below its boiling point is called Evaporation.
Whenever be the temperature at which evaporation takes place, the Latent Heat of Vapourisation must be supplied whenever a liquid changes into vapour or gas .
Explaination of Evaporation
Some particles in a liquid always have kinetic energy than the others . So, even when a liquid is well below its boiling point , some of its particles have enough energy to break the forces of attraction between the particles and escape from the surface of the liquid in the form of vapour or gas . Thus, the fast moving particles particles or molecules of a liquid are constantly escaping from the liquid to form vapour.
Factor affecting Evaporation
- Temperature ( the rate of Evaporation increases on increasing the temperature of liquid )
- Surface area ( the rate of Evaporation increases in increasing the surface area of the liquid ).
- Humidity ( when the humidity of air is low, then the rate of Evaporation is high , and water evaporates more readily)
- Wind speed ( the rate of Evaporation of a liquid increases with increasing wind speed ).
Most probably ask questions
What are the three States of Matter ?
Ans: The three States of matter are
- Solid
- Liquid
- Gas
Ans:During the conversion of state by a substance the molecules absorb latent heat from the surrounding and use it to remain to overcome the intermolecular force of attraction by increasing their energy levels so the heat absorbed is used for conversion of state without raising temperature.
Why does a desert cooler cool the better on a hot dry day ?
Ans : During summers the hot air is hot as well as free from humidity so on hot dry the rate of evaporation of water is more from a desert cooler it causes more cooling.
How does the water kept in an earthen pot become cool during summer
Ans: Earthern pots have small pores through which transpiration of water to the surface of the pot occurs and from the surface the evaporation of water takes place which causes the cooling of water kept in the earthen pot.
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