Physics GCSE AQA Year 9&10: Particle Model of Matter

How does evaporation cause the cooling of water?

. Evaporation is particles from the surface of a liquid escaping the liquid

. When they leave, they take energy with them

. This decreases internal energy and so the temp of the water

How do you find the volume of an irregular object?

. Put object into measuring cylinder filled with a fixed volume of liquid

. Measure amount of liquid that comes out / how much volume rises by

. Take this from the original volume of liquid

What is density?

How much matter is in a certain volume

What is internal energy?

Energy stored by the particles that make up the system

What is 1 m squared in cm?

10,000 cm squared

What is specific heat capacity?

the amount of energy required to raise 1kg of a material by 1 degree C

What is latent heat?

. The energy needed for a substance to change state

. When a change of state occurs, the energy supplied changes the internal energy but not the temperature

What is specific latent heat?

The amount of energy required to change the state of 1 kilogram of the substance with no change in temperature

What do you call the specific latent heat to change state from solid to liquid?

specific latent heat of fusion

What do you call the specific latent heat to change state from liquid to gas?

specific latent heat of vaporisation

What are the units for volume?

m³

What are the units for mass?

kg

What are the units for pressure?

pascals (Pa)

What are the units for area?

m²

What are the units for force?

Newtons (N)

What are the units for specific heat capacity?

J/kg°C

What are the units for specific latent heat?

J/kg

What can the particle model be used to explain?

. the different states of matter

. differences in density

If the mass of a solid is 1kg, what would it be as a liquid and as a gas?

1kg (It always stays the same!)

What type of change is a change of state?

Physical change

How is a physical change different from a chemical change?

In a physical change, the material recovers its original properties if the change is reversed

What is the particle model?

. Everything is made up of particles - either atoms or molecules - which are constantly moving

. How these particles are held together determines whether they are a solid, liquid or gas

Describe the particle model of a solid

. Strong forces between particles

. Can vibrate slightly

. Can't move around freely

What are the properties of solids?

. Incompressible/have a fixed volume

. Do not flow

. Hard to change the shape of

. Denser than gas

Describe the particle model of a liquid

. Forces between particles aren't as strong as in solids

. Particles are close together but can move

What are the properties of a liquid?

. Relatively incompressible/hard to change volume because the particles are close together

. They flow

. Easy to change the shape of

. Denser than gas

Describe the particle model of a gas

. No forces between particles

. Can move freely and at random

. Particles usually further apart than in a solid or liquid

What are the properties of a gas?

. Compressible

. They flow

. Easy to change the shape of - expand to take up volume of container

. Less dense than a solid or liquid

What is boiling point?

the temp at which a liquid will evaporate as fast as it can

How do you calculate internal energy?

sum of kinetic energy of particles + sum of potential energy of particles

Explain the differences in density between the different states of matter in terms of the arrangement of atoms or molecules.

Solids are the most dense due to their tightly packed structure. This means that for the same volume they have a larger mass so a higher density.

What is (gas) pressure

The force exerted by gas particles as they collide with the sides of a container. Pressure is due to the sum of all these forces.

describe the movement of gas particles

. random speeds

. in random directions

What happens when we increase the temperature of a gas?

. Particles have more kinetic energy, so they:

. Move faster (they move at different speeds so the average increases)

. On average, hit the sides with more force

. On average, hit the sides more often

So increasing the temperature therefore increases the pressure

Why can heating produce a change of state?

Heating = more energy in particles = enough potential energy to escape = change of state

What is the change of state from solid to gas called?

sublimation

What is the change of state from gas to liquid called?

Condensation

What are the units for density?

kg/m³

What is 1ml equivalent to?

1 cm³ (don't just x100 to convert to meters - it's cubed!)

Still learning (17)

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