Particle movement Flashcards
Particles in a solid
Very close together
Arranged in a regular pattern
Vibrate but don’t move
Particles in a liquid
Close together
Not arranged in a regular pattern
Can move around each other
Particles in a gas
Far apart
Not arranged in any pattern
Move very rapidly
Density
Tells us the mass for a given volume
High density
A high mass packed into a smaller volume
Eg a very heavy small thing like a brick
Low density
Lower mass packed into a higher volume
Eg a very light big thing like a tissue
Density equation
= mass(kg)
—————
Volume (m3)
Density unit
Kg/m3
What density do solids have?
A high density
Because they have lots of particles packed in its volume since they don’t move around
What density do liquids have?
Usually high
Because like solids they have particles close together in a volume
What density do gases have?
Low density
Because the particles are far apart = small mass for their volume
Polystyrene
A solid yet has a low density
Because it has an open structure with many air spaces
Why do all states have kinetic energy?
Because their particles are either moving or vibrating around each other = movement
Potential energy
The energy between particles as intermolecular forces or chemical bonds
Internal energy
The energy caused by both potential energy AND kinetic energy
Total energy stored inside particles of the system
How do we change state?
Increase its internal energy until it reaches its melting or boiling point = changed state
Melting
Solid to liquid
After increasing temperature
Increases internal energy
Boiling
Liquid to gas
After increasing temperature
Increases internal energy
Condensation
Gas to liquid
After decreasing temperature
Reduces internal energy
Freezing
Liquid to solid
After decreasing temperature
Reduces internal energy
Sublimation
Solid to gas
By increasing temperature
What happens to mass when we change state?
DOESN’T CHANGE because conserved
What type of change is changing state?
Physical so we can reverse it back to its original state
If you change state by cooling how does it affect mass?
It doesn’t
The volume will decrease but the density is increased
If you change the state by heating how does it affect mass?
It doesn’t
On a heating graph what does the straight line represent?
The material is changing state
But not changing in temperature
Because the energy taken in is weakening/breaking the forces of attraction to change state
When we change state do we change the temperature of the material?
No because the energy taken is is used to break/make forces of attraction
Melting point
The temperature a substance melts at
Boiling point
The temperature a substance boils at
Cooling graph
Shows the temperature a substance follows as it decreases in temperature
Specific latent heat
The amount of energy required to change state of 1kg of the substance with no change in temperature (because the temperature is used to break the bond)
Specific latent heat of fusion
Energy required to change 1kg of substance to solid —> liquid with no change in temperature
Specific latent heat of vaporisation
Energy required to change 1kg of a substance from a liquid to a vapour with no change in temperature
Energy for a change of state
Mass(kg) x specific latent heat (J/kg)
What is specific latent heat measured in?
J/kg
When calculating specific latent heat what is the mass measured in?
Kg
Pressure of a gas
Due to particles colliding with walls of the container
Pressure of a gas
Due to particles colliding with walls of the container
What increases the pressure of a gas?
Increase the number of collisions per second
Increase the energy of each collision
How can we actively increase the pressure of a gas?
Increase the temperature
How does increasing the temperature increase the pressure?
At low temperature particles have low kinetic energy
So fewer collisions per second as well as low energy collisions
But at high temperatures = particles have higher kinetic energy so more high energy collisions per second
What is the force in a gas container like?
Acts at right angles to the container over its area
What does increasing the volume do to the gas?
Decrease the pressure because the particles have to travel further before colliding with walls
So less collisions per second = lower pressure
Relationship between pressure and volume of a gas
They are inversely proportional
Increasing volume = decrease pressure
Gas pressure equation
pressure (Pa) x volume (m3) = constant
ONLY if temperature is constant
Force applied on a container with a gas in it
We have done work, (transferring energy by a force)
So energy transferred to particles
Increases internal energy
Increases temperature of the gas
Why do bicycle pumps increase in temperature?
Work applied to container
Gas particles have energy transferred to them
Increases their internal energy
Increases temperature
