Particle model of matter Flashcards
Define density.
Mass per unit volume
What units are used for density?
Kgm^-3 OR g/cm^3
What does the particle model theory tell you?
All matter is made of atoms, states the arrangement/movement in solids, liquids and gases.
Explain the arrangement of particles in solids.
- Tightly packed in rows.
- Vibrate about a fixed position.
- Definite shape + volume.
Explain the arrangement of particles in liquids.
- Closely packed particles.
- Particles flow.
- No definite shape, but definite volume.
Explain the arrangement of particles in gases.
- Sparse/distanced particles.
- Random motions.
- No definite shape or volume.
RP5: Explain how to find the density of a regularly shaped object.
- Place on a balance to find mass, do 3 times to ensure no random errors.
- Find the volume by finding lengths and use a formula.
- p = m/v
RP5: Explain how to find the density of an irregularly shaped object.
- Place on a balance to find mass, do 3 times to ensure no random errors.
- Fill Eureka/displacement can with water until its sprout.
- Place an empty measuring cylinder below the sprout.
- Lower object into the can slowly, water should displace into measuring cylinder.
- Repeat 3 times and use p= m/v.
RP5: Explain how to find the density of a liquid.
- On a balance, find the mass of an empty measuring cylinder.
- Fill cylinder with liquid and note volume of liquid.
- Calculate mass of liquid.
- Repeat 3 times and use p= m/v.
Name the changes of state.
Solid-liquid: melting
liquid-gas: evaporation
solid-gas: sublimation
gas-liquid: condensation
liquid-solid: freezing
Explain how changes of state occur.
Heat is needed, the particles gain KINETIC energy so they begin to vibrate about their fixed positions, but to change state their kinetic store needs to be full so their potential store gains energy to overcome the IMF to break free from fixed positions.
Define internal energy.
The total energy store in a system due to motion by particles in their fixed positions.
What happens to temperature during changes of state?
Remains constant because kinetic energy stays the same
Define specific latent heat.
The amount of energy needed to change states of 1kg of a substance.
What’s specific latent heat of fusion and of vaporisation?
Fusion: changing states solid-liquid or liquid-solid
Vaporization: changing states liquid-gas or gas-liquid
What is specific latent heat?
Amount of energy required to change the state of 1 kg of a substance with no temperature change.
What’s the formula for specific latent heat?
Thermal energy/mass
What is Brownian motion?
Random motion of particles, which causes particles to collide with walls of containers and other particles (pressure) because of more force.
Define pressure.
Force per unit area.
What’s the formula for pressure?
Force/ Area
When volume is decreased, what happens to pressure?
Increases during compression
