Particle Model of Matter Flashcards
(36 cards)
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
Measure of how closely packed the particles are in a substance
Unit of density
Kg/m³
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
- measure 50ml of liquid in measuring cylinder
- place beaker on balance, zero the balance
- pour 10ml of liquid into cylinder, record mass and volume
- pour another 10ml 4 times into cylinder repeatedly until cylinder is full, recording total volume and total 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 can happen as you increase energy of particles of system
- raise in temperature of system
OR - change of state
What determines size of temperature change in substance
- mass of substance
- specific heat capacity of substance
- total energy supplied to system
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
