P13: Kinetic Theory Flashcards
Gas > Liquid
Condensation
Liquid > Gas
Vaporisation/ Boiling
Solid > Liquid
Melting
Liquid > Solid
Solidifying/ Freezing
Solid > Gas
Sublimation
Gas > Solid
Condensation
Vibrate in a fixed position.
Keeps its shape.
Least Energy.
In contact with each other.
Can move around randomly, so has no fixed shape.
Middle Energy
Move about at random much faster.
Much farther apart.
Much lower density.
Most energy
Specific Heat Capacity
Energy needed by 1kg of the substance to raise its temperature by 1oC.
Specific Heat Capacity (J/kgoC) =
Energy Transferred (J)/ Mass (kg) x Temperature Change (oC)
The greater the mass of an object…
… The more slowly its temperature increases when it is heated.
When does evaporation take place?
At any temperature.
When does boiling take place?
At the boiling point
When a pure substance is changing state…
… The temperature stays the same.
Latent Heat
The energy supplied to a substance when it changes state. Called ‘latent’ (hidden) because the energy it supplies does not change the temperature at the melting/ boiling point.
Fusion
Often used to describe melting because different solids can be ‘fused’ when they melt.
Evaporation
Occurs on the surface of a liquid under its boiling point.
Specific Latent Heat of Fusion
energy needed to melt 1kg of a substance with no change of temperature.
What is the unit of specific latent heat?
J/kg
Specific Latent Heat of Fusion (LF) =
Energy (j) / Mass (kg)
Specific Latent Heat of Vaporisation (Lv) =
Energy (j) / Mass (kg)
Specific Latent Heat of Vaporisation
The energy needed to change 1kg of a substance at its boiling point from liquid to vapour.
