Particle Model of Matter Flashcards
Solids
- strong forces of attraction hold particles together in fixed regular arrangement
- particles don’t have much energy so can only vibrate in fixed positions
Liquids
- weaker forces of attraction between particles
- particles close together but can move past each other
- form irregular arrangements
- more energy than particles in solid so can move in random directions at low speed
Gases
- almost no forces of attraction between particles
- particles have more energy than in liquid and solids so are free to move constantly in random directions and speeds
Pressure
- when particles collide with the wall of their container they exert pressure
- gas pressure is the total force exerted per unit of area
What happens to pressure as you increase temperature
It increases
How does increasing temperature increase pressure
- particles have more kinetic energy so travel faster and hit the sides of the container more often in a given amount of time
- each particle has a larger momentum so exerts a larger force when colliding with the container
Density triangle
- DMV
- D - density
- M - mass
- V - volume
Density
How closely packed the particles are in a substance
What happens to the density of a material as you compress it
It increases
Why does a material’s density increase as you compress it
- the particles move closer together
- volume is decreasing
Density of regular solid practical
- measure object’s mass with balance
- measure with ruler/tape measure length, width, height
- then calculate density with mass/volume
Density of irregular solid practical
- measure object’s mass with balance
- fill eureka can with water and submerge solid in it
- record volume of object - volume of water displaced into measuring cylinder
- calculate density with mass/density
Density of liquid practical
- place measuring cylinder on balance and zero the balance
- pour 10ml of liquid into cylinder and record mass
- pour another 10ml into cylinder repeatedly until cylinder is full, recording total volume and mass each time
- calculate density of each measurement with mass/volume
- find average density
Internal energy
Total energy stored in kinetic and potential stores of all particles in a system
What happens to a system’s internal energy when you heat it
It increases
What determines size of temperature change in substance
- mass
- specific heat capacity
- energy output
When does change of state occur
When substance is heated enough, particles have enough energy in kinetic store to break bonds holding them together
What happens when you melt a solid
It becomes a liquid
What happens when you boil a liquid
It becomes a gas
What happens when you condense a gas
It becomes a liquid
What happens when you freeze a liquid
It becomes a solid
Change of state from solid to gas
Sublimation
State change from gas to solid
Deposition
What type of change is state change
Physical
What happens to particles as they are condensed or frozen
- bonds form between them, releasing energy
- internal energy increases
Specific latent heat
The amount of energy needed to change 1kg of a substance from one state to another without changing its temperature
Specific latent heat of fusion
Specific latent heat for changing between a solid or liquid
Specific latent heat of vapourisation
Specific latent heat for changing between a liquid and gas
