P3 - Particle Model of Matter Flashcards
1
Q
What does the particle model of matter say?
A
Everything is made up of matter as tiny balls
2
Q
Solids
A
- Strong forces of attraction hold the particles close together in a fixed, regular arrangement
- The particles don’t have much energy so they can only vibrate around their fixed positions
3
Q
Liquids
A
- Weaker forces of attraction between the particles
- The particles are still close together, but can move past each other, and form irregular arrangments
- They have more energy than the particles in a solid (they move in random directions at low speeds)
4
Q
Gases
A
- Almost no forces of attraction between the particles
- They particles have more energy than in liquids and solids - they’re free to move, and are constantly moving with random directions and speeds
5
Q
What is pressure?
A
The force exerted per unit area
6
Q
How do colliding gas particles create pressure?
A
- Because they are free to move around, they bang into each other and whatever else happens to get in the way
- When they collide with something, they exert a force on it
- So in a sealed container, the outward gas pressure is the total force exerted by all of the particles in the gas on a unit area of the container walls
7
Q
What happens if you increase the temperature of a gas?
A
- You transfer energy into the kinetic energy stores of its particles
- The temperature of a gas is related to the average energy in the kinetic energy stores of the particles in the gas. The higher the temperature, the higher the average energy
- Additionally, for a constant volume, increasing its temperature increases its pressure
- These factors both increase the total force exerted on a unit are, so the pressure increases
8
Q
What is density
A
A measure of the ‘compactness’ of a substance. It relates the mass of a substance to how much space it takes up
9
Q
Units of density
A
kg/m^3 (or g/cm^3)
10
Q
Density equation
A
Mass/Volume
11
Q
What does the density of an object depend on?
A
What it’s made of and how its particles are arranged
12
Q
Dense vs less dense materials characteristics
A
- A dense material has its particles packed tightly together
- Particles in a less dense material are more spread out
- This means that density varies between different states of matter (usually solids are generally denser than liquids, and gases are usually less dense than liquids)
