What is density?
Density is a measure of the ‘compactness’ of a substance.
What is the equation for density?
Density=mass divided by volume.
What does the density of an object depend on?
What it’s made of and how the particles are arranged.
What are the particles like in a less dense material?
They are spread out.
What are the three states of matter?
Solids,liquids and gases.
What is the force of attraction like for solids?
What is the force of attraction like for liquids?
Weaker than solids but stronger than liquids.
What is the force of attraction like for gases?
How much energy does a solid have?
Not that much -they can only vibrate about their positions.
How much energy does a liquid have?
More energy than a solid but not as much as a gas.
How much energy does a gas have?
A lot because the particles are free to move.
How do the particles in a gas behave?
They travel in random directions at high speeds.
Does a gas have a high density or a low density?
Does a solid have a high density or a low density?
How do you find the density of a solid object?
1) Use a balance to measure the mass.
2) Submerge the object in a eureka can filled with water.
3) The water displaced by the object will be transferred to the measuring cylinder.
4) Record the volume of the water in the measuring cylinder.
5) use the volume and mass to work out density in the formula.
How do you find the density of a liquid?
1) place a measuring cylinder on a balance and zero it.
2) pour 10ml of the liquid into the measuring cylinder and record the mass.
3) pour another 10ml into the measuring cylinder repeating the process until it is full, recording the total volume and mass each time.
4) for each measurement use the formula to find the density.
5) take an average of results.
When will a change in state occur?
When the substance is heated enough.
What happened in a change of state?
The particles are heated with transfers thermal energy to kinetic energy which means they have enough kinetic energy to break their bonds.
What is the process of making a solid to a liquid?
What is the process of making a liquid to a gas?
What is the process of making a solid to a gas?
What is the process of making a liquid to a solid?
What is the process of making a gas to a liquid?
What happens if you reverse a change of state?
The substance will return to it’s original form get back to it’s original properties.
Does the number of particles change in a change of state?
No-they are just arranged differently.
What happens to the internal energy of a substance when it is condensing or freezing?
Why does the internal energy of an object decrease when it is condensing or freezing?
Bonds form between particles which releases energy leading to a decrease.
What is latent heat?
The energy needed to change the state of a substance.
What happens to the internal energy of a substance when it is melting or boiling?
Why does the internal energy of a substance increase when it is melting or boiling?
Energy is being put into it leading to an increase.
In a substance that is melting or boiling what is the energy used for?
Breaking intermolecular bonds.
What is specific latent heat?
The amount of energy needed to change 1kg of it from one state to another without changing it’s temperature.
What is specific latent heat in cooling?
The energy released by a change in state.
What is the specific latent heat called for changing between a solid and a liquid?
Specific latent heat of fusion.
What is the specific latent heat called for changing between a liquid and a gas?
Specific latent heat of vaporisation.
What is the formula for specific latent heat?
specific latent heat =energy divided by mass.
What is the temperature of a gas related to?
The average energy in the kinetic stores of the particles of the gas.
The higher the temperature the…
Higher the average energy.
What happens when particles collide?
They exert a force on it.
What is the outward gas pressure in a sealed container?
The total force exerted by all of the particles in the gas on a unit area of the container walls.
What do faster particles and more frequent collisions lead to?
An increase in net force.
Pressure and volume are…