particle model Flashcards
How do you find density?
mass/ volume
particle arrangement in a solid
- very close
- regular pattern
- vibrate, cannot move
particle arrangement in liquid
- close
- no regular pattern
- can move around each other
density in states of matter, why, and exceptions
solid: high as particles are closely packed together, more mass in given volume
liquid: high as particles are closely packed together, more mass in given volume
gas: low as particles are far apart, less mass in given volume
polystyrene: solid with low density, as it is full of air spaces
particle arrangement in gas
- far apart
- no pattern
- move rapidly
density in states of matter, why, and exceptions
solid: high as particles are closely packed together, more mass in given volume
liquid: high as particles are closely packed together, more mass in given volume
gas: low as particles are far apart, less mass in given volume
polystyrene: solid with low density, as it is full of air spaces
state change from solid to gas and liquid to gas
sublimation
evaporation (only on surface)
why is changing state not a chemical change? what change is it?
physical change as materials will recover original properties if change is reversed
how to find density of regular objects (dimensions easily measured)
find mass: mass balance
find volume: ruler and calculate
find density
how to find density of irregular objects (dimensions not easily measured)
find mass: mass balance
find volume: fill eureka can with water. place object in water. water displaced flows into measuring cylinder
find density
what is specific heat capacity and what is it used for
amount of energy needed to raise 1kg of substance by 1 degree
- to find energy stored/released in system as temp changes
What is measured on a heating graph
temperature and time
what do flat spots show on heating graph
substance has reached latent heat, and is changing state.
energy put in is used for breaking/making bonds rather than to change temp - internal energy store increases
what is specific latent heat
energy needed to change state of 1kg of substance without changing temp
what is the specific latent heat for changing between a solid and liquid called
Specific latent heat of fusion
What is the specific latent heat for changing between a liquid and a gas called?
specific latent heat of vaporisation
describe pressure in gases and factors affecting it
particles colliding with walls causes net force at right angles to walls of container. this force causes pressure
- number of collision
- energy
how to change pressure in gas
change temp
- low temp: low pressure.
lower kinetic energy, fewer collisions per sec, lower energy collisions.
- high temp: high pressure.
higher kinetic energy, more collisions per sec, higher energy collisions
change volume
- high volume: low pressure.
more space between particles, fewer collisions per sec
- low volume: high pressure.
less space between particles, more collisions per sec
doing work
- applying force does work, increasing the internal energy of the gas
- internal energy involves kinetic energy. higher kinetic energy in particles means temperature increases
why does a tyre get warmer when pumped
when pumped, work is done, increasing internal energy. internal energy involves kinetic energy, which increases temperature.
what is specific heat capacity measured in?
j/kg°c
what is specific latent heat measured in
j/kg
compare potential energy of states
gas has highest
solid has lowest
