Kinetic Particle Theory Flashcards
Why does a solid have a fixed shape?
Particles of a solid are:
- closely packed in an orderly manner
- held together by very strong forces of attraction
- have enough kinetic energy to only vibrate about fixed positions
- cannot move about freely
Why does a solid have a fixed volume?
- cannot be compressed since its particles are already very close to one another
KINETIC PARTICLE THEORY ☄
- states that all matter is made up of tiny particles and that these particles are in constant random motion
Why does a liquid not have a fixed shape?
Particles of a liquid are
- arranged in a disorderly manner
- have weaker forces of attraction than particles of a solid
- have more kinetic energy then particles of the same substance in solid state and are not held in fixed positions
- can move freely throughout the liquid
Why does a liquid have a fixed volume
The particles of a liquid are further away from one another than the particles of a solid. However, the liquid particles are still packed quite closely together.
Why does has not have a fixed shape
Particles of a gas
- spread far apart from one another
- have weaker forces of attraction than the particles of a liquid
- have a lot of kinetic energy and are not held in fixed positions
- can move rapidly in any direction
Why does gas not have a fixed volume
- particles of a gas have a lot more space between them than particles of a solid or gas
- the large space between the particles allows the gas to be easily compressed when pressure is applied
- since a gas can be compressed it has no fixed volume
Melting process
- heat energy is absorbed by the particles of a solid
- heat energy is converted into kinetic energy
- particles start to vibrate faster about their fixed positions
- when the temperature is high enough, the vibrations of the particles become sufficient to overcome the forces of attraction between them
- the particles begin to break away from their fixed positions
- particles are no longer in their fixed positions
- substance is now a liquid
- particles can move freely throughout the liquid
Why does temp not rise during melting even though heating continues ?
Heat energy taken in by particles of the solid is used to overcome the forces of attraction holding the particles in fixed positions
Freezing process
- particles lose kinetic energy and begin to move more slowly
- when temperature is low enough, particles no longer have enough energy to move freely
- particles start to settle into fixed positions
- all particles have settled into fixed positions
- substance is now a solid
- particles can only vibrate about fixed positions
Why does temp not change during freezing
- heat energy is released as the particles of the liquid are attracted to each other to form a solid.
- this heat energy is given out to the surroundings
Boiling process
- heat energy is absorbed by particles of the liquid
- heat energy converted to kinetic energy
- particles move faster as temp rises
- when temp is high enough, the particles have enough energy to overcome the forces of attraction holding them together
- particles are now spread far apart
- substance is now a gas
- particles can move in any direction
Why does temp remain the same during boiling
- heat energy is taken in by the particles of the liquid is used to overcome the forces of attraction between the particles
Boiling VS evaporation
Boiling occurs only at boiling point / evaporation occurs at temps below boiling point
Boiling occurs throughout the liquid/ evaporation only occurs at the surface
Boiling occurs rapidly/ evaporation occurs slowly
Volatile liquids
Petrol, ethanol, ammonia, acetone, dichloromethane
