1 IGCSE CHEMISTRY
STATES OF MATTER
Specification Point 1.1:
Understand the three states of matter in terms of the arrangement, movement & energy of
the particles
Particles in a solid
Arrangement:
Regular repeating pattern
Close together, touching each other
Movement:
Vibrate about fixed positions but do not move apart
Have least kinetic energy
Forces between particles:
The particles have strong forces of attraction between them
Shape:
Fixed shape and volume
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2 IGCSE CHEMISTRY
Particles in a Liquid
Arrangement:
The particles in a liquid are arranged randomly
Close together and touching each other
Movement:
Move around and slide past one another
Have more kinetic energy than solid but less than gas
Forces between particles:
Not as strong as solid
Shape:
No fixed shape (takes shape of container) but fixed volume
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3 IGCSE CHEMISTRY
Particles in a Gas
Arrangement:
Irregular
Far apart
Movement:
Have highest kinetic energy compared to solids and gases
Forces between particles:
Non-existent
Shape:
No fixed shape or volume
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4 IGCSE CHEMISTRY
Specification Point 1.2:
Understand the interconversions between the three states of matter in terms of:
– the names of the interconversions
– how they are achieved
– the changes in arrangement, movement & energy of the particles
Interconversions between the three states of matter
Melting the process of converting from solid to liquid due to increase in temperature.
Melting point the temperature at which a solid starts to melt, eg. ice melts at 0 °C.
Boiling the process of converting from liquid to gas due to increase in temperature. Also
known as vaporisation.
Boiling point the temperature at which a liquid starts to boil, eg. water boils at 100 °C.
Condensation the process by which a gas turns to liquid.
Sublimation the process by which a solid turns directly to gas without melting.
Solidification the process by which a gas turns directly to solid.
Evaporation the process by which a liquid turns to a gas below its boiling point.
Volatile liquids that evaporate at room temperature.
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5 IGCSE CHEMISTRY
Arrangement, Movement & Energy
Solid to Liquid
Heat solid until it melts. When a solid is heated the particles gain kinetic energy and start to
vibrate faster about their fixed position. When the temperature is high enough, the vibration
of particles becomes sufficient to overcome the forces of attraction between them. The
particles begin to break away from their regular pattern. They can now slide past each other.
The solid becomes a liquid.
Liquid to Solid
Cool liquid until it freezes. When a liquid is cooled, the particles lose their kinetic energy.
When the temperature is low enough, the particles no longer have the energy to slide over
each other. The forces of attraction can hold the particles together in a regular pattern. The
substance becomes solid.
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6 IGCSE CHEMISTRY
Liquid to Gas
Heat the liquid until it boils. When a liquid is heated, the particles gain kinetic energy and
mover further apart. Eventually, the attractive forces in the liquid are broken. Bubbles of
gaseous particles escape from the liquid. The substance becomes gas.
Gas to Liquid
Cool the gas until it condenses. When a gas is cooled, the particles lose kinetic energy and
the attractive forces become great enough to keep the particles closer together as a liquid.
Solid to Gas
Heat the solid until it sublimes. The solid particles gain kinetic energy and vibrate faster.
Eventually, the forces of attraction between the particles are completely broken and they
escape from the solid as a gas.
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7 IGCSE CHEMISTRY
Questions
Year 9 Chemistry text book
Page 20 Question number -- 1, 2
Page 21 Question number -- 3, 4
Page 24 Question number –1, 2, 3, 4, 5
Page 25 Question number –1, 2,
Page 26 Question number –3, 4,
Page 27 Question number –5,
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