P6: Molecules And Matter Flashcards
What is Density?
The mass per unit of volume (of an object)
What is the equation for density?
Density = Mass/Volume
How do you find the density of a regular object?
You find the mass and find the volume
You then subsitute these measurements into the equation: Density = Mass/volume too find the density
How do you find the density of an irregular object?
1) First you must find the mass of your object
2) Secondly you must fill a eureka can up to the sprout, allowing excess water to drain out.
3) Gently place your irregular object into the eureka can, collecting any water which falls out through the sprout in a beaker.
4) Transport the displaced water from the beaker too a meassuring cylinder to measure the volume of the water.
5) Use your now collected volume and mass to calculate the density using the equation: Density = Mass/volume.
Describe the properties of a solid
- Particles are not free to flow
- Particles in a fixed shape
- Fixed volume
- More dense than a liquid or gas
Describe the properties of a liquid
- Particles are free to flow
- Particles are not in a fixed shape
- Fixed volume
- More dense than a gas
Describe the properties of a gas
- Particles are free to flow
- Particles are not in a fixed shape
- Not a fixed volume
- Less dense than a solid or liquid
What are the changes of state between gases and liquids called?
Liquid —> Gas = Evaporation
Gas —> Liquid = Condensation
What are the changes of state between gases and solids called?
Solid —> Gas = Sublimation
Gas —> Solid = Deposition
What are the changes of state between liquids and solids called?
Solid —> Liquid = Melting
Liquid —> Solid = Freezing
What is the conservation of mass?
Substances do not gain/lose any mass after a change of state
What is the melting point of a substance?
The temprature at which a substance changes from a solid too a liquid
What is the boiling point of a substance?
The temprature at which a substance changes from a liquid to a gas
Why do substances not gain any temperature when changing states?
As all of the energy is being put into breaking the bonds between the particles too change state
What is internal energy?
The particles in a substance have energy, this is called ‘internal energy’ - this relates to the particles motion and position
What is the equation for internal energy?
Internal energy = Kinetic energy + potential energy
What is latent heat?
The energy transferred when a substance changes state
What is specific latent heat of fusion?
The energy supplied to change 1kg of a substance from solid to liquid state
What is the specific latent heat of vaporisation?
The heat needed to turn 1kg of liquid into gas at its boiling point
What is the equation for specific latent heat?
Specific latent heat = Energy (J) / Mass (kg)
What is gas pressure caused by?
Gas pressure is caused by the random collisions of particles against any surface that the gas comes into contact with
What is the brownian motion?
The random (unpredictable) movement of particles in fluids as they constantly collide with other molecules
If a sealed container is heated, explain what happens to the pressure exerted on the container?
When the container is heated, the gas particles inside begin to vibrate faster due to an increase in kinetic energy. This means the particles collide with the surface of the container more frequently and with more force. This results in more pressure being exerted, as the equation for pressure is force/area
