C1.1 - The Particle Model Flashcards
What is a particle?
A particle is a tiny bit of matter
What is the particle model?
The particle model describes how particles are arranged and how they move in solids, liquids and gases
What is the movement of particles in a solid
They vibrate around fixed positions
What is the movement of particles in a liquid
They move around each other
What is the movement of particles in a gas
They move quickly in all directions
Why can’t you compress a solid or liquid
There is no space for the particles to move into
Why does a solid have a fixed shape
It’s particles vibrate around fixed positions and cannot move from place to place
Is matter continuous
No (it is made from particles).
Why do scientists use models?
- To explain the things they see happening
- to solve problems
- to make predictions
- to develop scientific understanding
What is a physical change
A physical change happens when a substance changes state or shape or breaks into pieces.
NO NEW SUBSTANCES ARE MADE
They are reversible
Examples of a physical change
- freezing juice to make an ice lolly
- mixing sand and water
- dissolving sugar in water
- melting butter
What is a chemical change?
A chemical change is a change that produces ONE OR MORE NEW SUBSTANCES.
(They might look different or may be in a different state),
They are irreversible.
Examples of chemical changes
- cooking eggs (or other food)
- steel rusting
- an acid reacting with an alkali to make salt and water
What happens to particles during a physical change (when it changes state)
It’s particles stay the same but their arrangement and movement change.
What happens to particles during a chemical change?
The particles break up and then join together in different ways
What is an atom?
An atom is the smallest particle that makes up a substance
How do you calculate the ratio of distance to diameter (the space between atoms)?
Distance between atoms ➗ diameter of atom
What are the limitations of the particle model?
It does not take into account
- the forces between particles
- the size of particles
- the space between particles
Why does the volume of a substance increase when it melts?
Thus us because some of the forces of attraction are overcome and the particles can move around each other
Are the collisions between particles elastic or inelastic
In the particle model the collisions between particles are inelastic. Energy is transferred from the particles to the surrounding when particles collide. In reality, particle collisions are elastic as energy is not transferred to the surroundings during a collision
What is matter?
Anything that has mass
