General overview (particle model)

Describe the arrangement and movement of particles in a solid

Tightly packed, regular arrangement, vibrate in fixed positions

Describe the arrangement of particles in a liquid

Close together, can move past each other, vibrate and move freely at high speeds

Describe the arrangement of particles in a gas

Well separated, no regular arrangement, vibrate and move freely at high speeds

Formula for density

Density=mass/volume

How does density of a substance depend on the different states of matter?

Solids and liquids have similar densities as the space between particles doesn’t change. Gases have low densities as there is more space between atoms so they occupy a larger volume while mass stays constant.

What happens when substances change state?

Mass is conserved, change is only physical, the change in state is reversible

How does heating a system change the energy stored within the system?

Particles have more energy so will vibrate more, so the temperature of the system increases, and it can cause a change in state

What is specific heat capacity?

The energy needed to raise the temperature of 1kg of substance by 1 degree Celsius

What is specific latent heat?

The energy needed to change the state of 1kg of substance without a change in temperature

How does thermal insulation reduce unwanted energy transfer?

Less heat is lost to the surroundings by trapping it

What is pressure like in a gas?

Particles move randomly

How does changing temperature of a gas affect the pressure of a gas of a fixed mass and volume?

Kinetic energy is transferred to particles, causing them to vibrate more. This increases the frequency of collisions between particles and walls of the container. The force exerted on the walls of the container is greater while the area stays the same. This means there is an increase in pressure

What is absolute zero?

-273 degrees C, 0 Kelvin

The temperature at which particles have no energy so cannot move

How can gases be compressed or expanded?

By changing pressure

How does changing volume affect the pressure of a gas of fixed mass and constant temperature?

Particles in a gas collide more frequently with the walls of the container. This is because the area that particles have to collide with decreases. More frequent collisions means higher force is exerted, meaning there is a higher pressure.

How does doing work on a gas increase temperature in a bike pump?

While using a pump, work is done on the gas. This is done against friction between the sides of the pump and the piston. Therefore energy is transferred, so particles move faster. This increases the temperature of the gas.