P3 Particle model of matter Flashcards
What is the equation for calculating density?
Density = mass/volume
What unit is density measured in?
Density is measure in
kilograms per metre cubed
kg/m3
What is the internal energy of a gas made up of?
The total of all the kinetic energy and potential energy of the particles.
Define specific heat capacity.
The energy required to raise the temperature of 1 kg of a substance by 1 degree Celsius.
Define specific latent heat.
The energy required to change the state of 1 kg of a substance at constant temperature.
What type of specfic latent heat produces a solid - liquid change?
Specific latent heat of fusion.
What type of specfic latent heat produces a liquid - gas change?
Specific latent heat of vaporisation.
(Triple only) For a fixed mass of gas at constant temperature, how are pressure and volume related?
pressure x volume = constant
What unit is pressure measured in?
Pascals (Pa) (same as Newtons per metre squared)
(Triple only) What effect does doing work on a gas have?
Increases the internal energy and can increase the temperature.
What is all the energy stored in a system by the particles called?
Internal energy.
It’s the sum of the kinetic energy and the potential energy of the particles.
For a fixed volume of gas, what effect does increasing the temperature of the gas have?
Explain why.
Increases the pressure.
This is because increasing the temperature makes the particles move faster, so the hit the walls with more force and more frequently. This increases the pressure.
If the temperature of a gas is constant, what effect will there be on the pressure if the volume of the container is decreased?
The pressure will increase.
(Triple only) In a bicycle pump, what is the effect of doing work on the gas in it?
The temperature will increase. (Doing work on the gas makes the particles move faster, meaning the temperature goes up)
How would you measure the density of a regular shaped object (a cuboid)?
Find the volume by measuring each dimension and multiplying them together.
Find the mass in kg by putting the object on an electronic balance.
Find the density by dividing the mass by the volume.
What causes pressure in a gas?
Gas pressure is caused by collision between the particles and the walls of the container.
The collisions cause a force to be exerted on the walls, and this causes an outward pressure.
How would you measure the density of an irregular shaped object (a rock or ransomly shaped piece of metal for example)?
Find the mass in kg by putting the object on an electronic balance.
Find the volume by using a Eureka can to measure the volume of water displaced when you put the object in the can.
Divide mass by volume to find density.
Why doesn’t the temperature change during a change of phase, e.g. melting?
During a phase change the energy is being used to break intermolecular bonds.
If the substance is turning in to a solid then the energy is used to make intermolecular bonds.
Why is the latent heat of vaporisation greater than the latent heat of fusion?
The latent heat of vaporisation is greater than the latent heat of fusion because it takes more energy to get the particles competely separate like they are in a gas, than to just break the bonds form solid to liquid.
