Hg
Name: Class 9
___________________________________________________________________________________________________________________________________
___________________________________________________________________________________________________________________________________
The Hg Classes (8
th
to 12
th
) By: Er Hershit Goyal (B.Tech. IIT BHU), 134-SF, Woodstock Floors, Nirvana Country, Sector 50, GURUGRAM +91 9599697178.
fb.me/thehgclasses linkedin.com/company/the-hg-classes instagram.com/the_hg_classes g.page/the-hg-classes-gurugram thehgclasses.co.in
Matter in our Surroundings
• Matter is made up of small particles.
• The matter around us exists in 3 states – SOLID, LIQUID and GASEOUS (GAS).
• Various attributes that define the 3 states (based on particle theory):
SOLID
LIQUID
GASEOUS
Shape
Definite
Indefinite
Indefinite
Volume
Definite
Definite
Indefinite
Inter-particle space
Minimum
Intermediate
Maximum
Inter-particle force of
attraction
Maximum
Intermediate
Minimum
Arrangement of
particles
Most Ordered
Layers of particles can slip and
slide
No order; particles move
randomly
Kinetic Energy of
particles
Minimum
Intermediate
Maximum
Compressibility
No
No
Yes
• The states of matter are inter-convertible by changing temperature of pressure.
Interconversion b/w states of matter:
• Boiling is a bulk phenomena. Particles from bulk (whole) of the liquid change into vapor state.
• Evaporation is a surface phenomena. Particles from the surface gain enough energy to overcome
forces of attraction present in the liquid and change to vapor state.
The rate of evaporation depends upon
o the surface area exposed to the atmosphere,
o the temperature,
o humidity and
o wind speed.
• Evaporation causes cooling. Some of its applications in daily life:
o Sweating
o Splashing of water in summers
o Water coolers
• Sublimation is the change of solid state directly to gaseous state without going through liquid state.
e.g. naphthalene balls and dry ice (solid carbon-dioxide) sublimate.
• Deposition is change of gaseous state directly to solid state without going through liquid state.
Hg
Name: Class 9
___________________________________________________________________________________________________________________________________
___________________________________________________________________________________________________________________________________
The Hg Classes (8
th
to 12
th
) By: Er Hershit Goyal (B.Tech. IIT BHU), 134-SF, Woodstock Floors, Nirvana Country, Sector 50, GURUGRAM +91 9599697178.
fb.me/thehgclasses linkedin.com/company/the-hg-classes instagram.com/the_hg_classes g.page/the-hg-classes-gurugram thehgclasses.co.in
• Latent heat of vaporisation is the heat energy required to change 1 kg of liquid to gas at atmospheric
pressure at its boiling point.
➔ That is why steam at 100
o
C will cause more burn than water at same temperature as steam has
latent heat of vaporisation.
• Latent heat of fusion is the amount of heat energy required to change 1kg of solid into liquid at its
melting point.
➔ That is why ice at 0
o
C causing more cooling effect than water at same temperature as water has
latent heat of fusion.
• During state changes temperature remains constant as extra heat energy given goes in separating the
particles and eventually gets stored as latent heat of fusion (solid to liquid) or vaporisation (liquid to
gas).
