P3

Density

This is how compact an object is:

Solids: These have

  • Strong forces of attraction holding their particles close together

  • Arranges in a regular structure

  • Usually have the highest density due to their compact nature

  • Usually require the most energy to break apart solid forces of attraction

  • Can only vibrate around a fixed position when heated

  • Cannot fit the shape of their container

  • Draw them close together and compact like So:

    So

Liquids, These have:

  • Weaker forces of attractions between each particle

  • Particles are close together but can move past each other

  • Form irregular arrangements

  • Less dense than solids (Mid density)

  • Move about randomly at low speeds

  • Can fit the shape of their container

  • Draw all of them touching with gaps like So’s brother:

So's brother

Gasses, These have:

  • Almost no forces of attraction

  • Have lots of energy

  • Move freely at high speeds

  • less dense than liquids (Lowest density)

  • Draw less than 4 with lines of motion to show that their fast moving like So’s cousin:

Kelvin

To find the density of an object you need to find its:

Mass and volume

Internal energy and changes of state

  • internal energy is the energy held inside the particles of on object:

  • E.g. The vibration of the particles as they get heated is their internal kinetic energy.

  • Or their GPE

  • If the internal kinetic energy is high enough then it can break the bonds between the particles changing its state

  • When an object is heated, its internal kinetic energy increases

Specific latent heat

  • As a substant heats up the line goes up

  • When the line is flat that means that the energy is going towards breaking the bonds rather than increasing the temperature

  • When the line goes down the energy is being lost to the surroundings

  • Which decreases the temperature

  • However when the line goes flat

  • Bonds are being made, which releases energy

  • Which stops the temperature decrease temporarily

Specific latent heat is the amount of energy needed to change the state of 1kg of substance without changing the temperature.

  • SLH of melting or freezing is called Specific latent heat of fusion

  • SLH of Boiling/ evaporation or condensation is Specific latent heat of vaporisation

Pressure

  • As you increase the temperature of a gas

  • you increase it’s kinetic energy

  • and you increase its speed

  • And it’s number of collisions

  • These collisions exert force on the inside of the gas’s container

  • Meaning that you increase the frequency of collisions when you increase its temp

  • And its force exerted

If you decrease the size of a gas’s container

Its pressure will rise

If you increase the temperature

Force will rise, increasing it’s pressure

Pressure = Force * Area

Pressure * volume = the constant

done…