States of matter Flashcards
Solid characteristics
- Fixed volume
- Fixed shape
- Strong attraction between particles
- Particles can’t move freely but can vibrate (low energy)
- Regular arrangement
- High density
- Can’t be compressed
- Can’t diffuse
- The particles are packed very closely together in a fixed and regular pattern
Liquid characteristics
- Fixed volume
- Acquires shape of container
- Forces of attraction between particles are less strong than between a solid
- Particles can freely move and slide over each other (greater energy)
- Irregular arrangement
- Medium density
- Can’t be compressed
- Slowly diffuse
Gas characteristics
- Not fixed volume
- Not fixed shape
- No or very weak forces of attraction between particles
- Particles move randomly and are spread out (highest energy)
- Irregular arrangement
- Low density
- Can be compressed
- Diffuse quickly
What happens to energy particles when they have more thermal energy?
More kinetic energy and the increased energy causes forces of attraction (bonds) to break allowing state changes to occur
Difference between pure and impure substance heating/cooling curve
Pure substances have a sharp melting and boiling point (the plateaus) while impure substances melt/boil over a range of temperatures
Explain melting in terms of kinetic particle theory
Requires heat energy which transforms to kinetic energy. Heating a solid causes its particles to vibrate more and at the melting point, particles gain enough energy to overcome the forces holding them in fixed positions.
Explain boiling in terms of kinetic particle theory
Heating a liquid gives the particles more energy, making them move faster. At the boiling point, particles have enough energy to completely overcome the forces keeping them together in the liquid state. They move apart to form a gas, where particles are far apart and move freely
What is evaporation
Evaporation occurs only at thesurfaceof liquids where high energy particles can escape from the liquid’s surface atlowtemperatures, below the b.p. of the liquid. (It’s a more superficial process than boiling)
Explain freezing in terms on kinetic particle theory
Particles lose kinetic energy and move much slower. This causes them to get closer together and forces of attraction hold them together in a fixed position making them a solid
Explain condensation in terms on kinetic particle theory
When a gas is cooled its particles lose energy and when they bump into each other they lack the energy to bounce away again, instead they group together to form a liquid
What happens if gas is heated in a fixed volume?
Temperature rises causing particles to move quicker as they have more kinetic energy. This causes harder an more frequent collisions with the container walls and each other causing an increase in pressure
What happens if gas is heated with fixed pressure?
As the temperature of a gas increases, the volume of the gas increases (with a constant pressure). This is because the particles of the gas increase in kinetic energy meaning they move faster and to avoid hitting each other and the wall (constant pressure) particles will naturally move further away from each other which therefore increases the volume.
Relationship between volume and pressure
Volume and pressure are inversely proportional
Effect on molecular mass on rate of diffusion
The smaller the molecular mass, the faster the rate of diffusion this is because the smaller the molecular mass, the less energy it needs to move. So, at the same energy, molecules with lower mass will move faster than molecules with more mass. This allows diffusion to occur faster.
