Matter Flashcards
What is density
A measure of the ‘compactness’ of a substance
What is the equation for density
Density = Mass / volume
What are the units for density
g/cm3
kg/m3
Does density vary with size or shape
No
What does the density of an object depend on
What it is made of
What does the average density of an object determine
Whether it floats or sinks - float = lower density than the fluid
What are the three states of matter
Solid, liquid, gas
When a substance changed volume, what happens to the density
It also changes
What does heating a substance do to its thermal energy store
It increases the energy in it
What happens to materials that need to gain a lot of energy to warm up when they cool down
They release loads of energy
What is the specific heat capacity of a substance
The change in energy in the substance’s thermal store needed to raise the temperature of 1kg of that substance by 1’C
What happens to the particles in a substance when you transfer energy to the kinetic energy stores of the particles
They vibrate or move faster
What happens to the energy you put in when melting or boiling a substance
The energy is used for breaking intermolecular bonds rather than raising the temperature
What is the specific latent heat of a change of state
The amount of energy needed to change 1kg of it from one state to another without changing its temperature
Is specific latent head the same or different for different materials
Different
What is the specific latent heat for changing between a solid and a liquid called
The specific latent heat of vaporisation
What is the equation for thermal energy
Mass x specific latent heat
What is the kinetic theory
All matter is made up of very small, constantly moving particles
What is pressure
The force acting from particles per unit area
What is a closed system
Nothing can get in or out eg. a closed container
What does the pressure a gas exerts on its container depend on
How fast the particles are going and how often they hit the walls
What happens if you hold a gas in a sealed container with a fixed mass and volume and heat it
Energy is transferred to the kinetic energy stores of the gas particles and they mov faster
If a gas is cooled, what effect does it have on the particles
They have less energy and move less quickly
What causes low pressure
The gas is cooled as the particles hit the walls with less force and less often, so the pressure is reduced
