Please enable JavaScript.
Coggle requires JavaScript to display documents.
The particle model of matter (Density (States of matter (Liquid (particles…
The particle model of matter
Internal energy and changes in state
Internal energy is the sum of the total energy stored in the particles
Gravitational potential energy
Due to position
Kinetic energy
Vibrate / move around
Heating the substance transfers kinetic energy to particles (they move faster) increasing internal energy
this leads to:
A change in state
Changes in state occur when there is enough energy in the particle's kinetic energy store to break apart intermolecular bonds
A change in temperature
size of change depends on mass, specific heat capacity and input energy
Change in thermal energy (joules) = Mass (g) x Specific heat capacity x Temperature change (c)
Specific heat capacity is the amount of energy needed to heat 1kg of substance by 1 degree celsius
Changes of state
Is a physical change (chemical formula is unaltered)
If you freeze / reheat the substance it will have all of its original properties
The mass or number of particles does not change
solid --->MELTING --> liquid --> EVAPORATING ---> gas
gas --> CONDENSING --> liquid --> FREEZING --> solid --> SUBLIMATING --> gas
Density
Can be explained using particle model
depends on what its made of and particle arrangement
dense
particles are close together
less dense
Particles aren't as close together
If particles are moved closer together it becomse denser
States of matter
Liquid
particles
medium attraction
medium energy
can move past each other
irregular arrangement
random direction
low speed
medium density
Gas
particles
almost no attraction
free movement
highest energy
lots of movement
random direction
high speed
low density
Solid
particles
strong attraction
fixed, regular arrangement
little energy
little movement
close together
highest density
Specific latent heat
Latent heat
melting/boiling points
substance is heated
temperature does not rise
all energy put in is being used to break intermolecular bonds / change state
energy needed to change the state is called the latent heat
specific latent heat
amount of energy required to change the state 1kg of substance without a temperature increase
for cooling, the amount of energy released during the change of state of 1kg of substance without a temperature decrease
is different for different states
is different for different substances
Solid --> Liquid / Liquid --> Solid
Specific latent heat of fusion
Liquid --> Gas / Gas --> Liquid
Specific latent heat of vaporisation
energy = mass x specific latent heat
Particle motion in gas
movement
random direction
particles collide with each other and other 'things'
during collision they exert a force (and a pressure) on the 'thing'
in a sealed container the gas pressure is the total force exerted by all particles on a unit area of the container walls
smaller container
more particles hit walls
higher pressure
(smaller volume)
larger container
less particles hit walls
lower pressure
(larger volume)
pressure causes an overall outward force at right angles to the surface of the container
there is also pressure on the container from the air around it
this means when a balloon rises, the pressure from the air gets smaller, so the balloon expands as the pressure is larger on the inside
1 more item...
random speeds (generally high)
faster speeds means more collisions means more force means higher pressure
increasing the temperature increases the energy in particle kinetic energy stores
faster movement
the higher the temperature the higher the average energy
kinetic energy = 1/2 x mass x velocity squared
transfering energy by force is called doing work
doing work on a gas increases internal energy
bike pump: gas applies pressure to plunger, exerting a force, work has to be done against this force to push down the plunger
this transfers kinetic energy to the gas particles, increasing the internal energy