C1 Flashcards
What is a particle?
A tiny bit of matter
What is the particle model?
A model that describes how particles move in solids, liquids and gases
Describe the particle model of a solid?
Particles are in a REGULAR arrangement with the relative distance between particles being VERY CLOSE. The particles only VIBRATE AROUND FIXED POSITIONS.
Describe the particle model of a liquid?
The particles are arranged RANDOMLY with the relative distance between particles being CLOSED and the particles MOVE AROUND EACH OTHER
Describe the particle model of gases
The particles are in a RANDOM arrangement with the particles being FAR APART from each other and they MOVE QUICKLY IN ALL DIRECTIONS
What does a particle model explain?
You can’t compress a solid
A solid has a fixed shape and cannot flow
What is a physical change?
When a substance changes state, shape or breaks and no new substances are made - it is easily reversible
What are examples of physical changes?
Freezing juice to make an ice lolly
Mixing sand with water
Dissolving sugar in water
What is a chemical change?
Produces one or more new substances and are extremely difficult to reverse
What are examples of chemical changes?
Cooking eggs and cake etc…
Steel rusting
An acid reading with an alkali to make a salt and water
What happens to particles in a physical change?
The particles move around each other and the arrangement of the particles change
What happens to particles in a chemical change?
Particles break up and join together in different ways - new substances are made
What is the diameter of a helium atom?
62 x 10^-12 M
What are electrostatic forces?
Attractive forces between positive and negative charges - they become weaker the further apart the particles are
What are the limitations of the particle model?
Forces between particles
Size of the particles
Space between the particles
What is an atom (relative to elements)?
The smallest particle of an element that still has its chemical properties
What is a molecule?
Two or more atoms joined together by attractive forces called chemical bonds
What is 1 nanometre?
1x10^-9 M