P3 - Particle Model of Matter

What are the three common states of matter?

Solid, liquid, gas

How are particles arranged in a solid?

Particles are very close together in a regular pattern

Can particles in a solid move around?

No, they only vibrate in place

How are particles arranged in a liquid?

Particles are close together but in an irregular pattern

Can particles in a liquid move around each other?

Yes, they can flow past one another

How are particles arranged in a gas?

Particles are far apart and randomly arranged

How do particles move in a gas?

Rapidly in all directions

Which state of matter has particles with the most energy?

Gas

Which state of matter has particles with the least energy?

Solid

What is density?

The mass of a substance per unit volume

What is the formula for density?

Density = Mass ÷ Volume

What is the unit for mass in the density equation?

Kilograms (kg)

What is the unit for volume in the density equation?

Cubic meters (m³)

What is the unit for density?

Kilograms per cubic meter (kg/m³)

Is the density equation given in the AQA GCSE exam?

No, you must memorise it

How can you rearrange the density equation to find mass?

Mass = Density × Volume

How can you rearrange the density equation to find volume?

Volume = Mass ÷ Density

What is the density of an object with mass 150 kg and volume 0.3 m³?

150 ÷ 0.3 = 500 kg/m³

Why do solids usually have high density?

Because particles are tightly packed, so there is a lot of mass per volume

Why do liquids usually have high density?

Particles are still close together, so mass per volume is still high

Why do gases have low density?

Particles are far apart, so there is little mass in a large volume

What is a real-life example of a low-density solid?

Polystyrene

Why does polystyrene have low density even though it's a solid?

It has an open structure with many air spaces

What do air spaces in materials like polystyrene do?

Reduce the mass per volume, lowering the density

Under a microscope, what can be seen in polystyrene?

Lots of air spaces

What kind of diagram can model particle arrangement in states of matter?

Particle model diagrams

What should be shown in a particle diagram of a solid?

Tightly packed, regular pattern with particles vibrating

What should be shown in a particle diagram of a liquid?

Close particles, irregular pattern, able to move around

What should be shown in a particle diagram of a gas?

Widely spaced particles moving randomly and freely

Why is the particle model useful?

It helps explain physical properties like density

How does the particle model explain the high density of solids?

Lots of mass tightly packed into a small volume

How does the particle model explain the low density of gases?

Particles are spread far apart, so mass per volume is low

Is it possible for a solid to have low density?

Yes, if its structure contains a lot of air (like polystyrene)

How can you increase the density of a material?

Increase its mass or decrease its volume

How can you decrease the density of a material?

Decrease its mass or increase its volume

Does temperature affect density?

Yes, heating a substance usually decreases its density (expands volume)

Why does heating a gas lower its density?

Particles move faster and spread further apart, increasing volume

What should you always include in a density calculation answer?

Units (kg/m³) and the correct number of significant figures