Other Flashcards
1
Q
Molecule
A
A cluster of atoms, caused by a chemical reaction
2
Q
Physical changes (definition)
A
An action that doesn’t change the nature of a substance
- it is reversible
3
Q
particle theory = kinetic theory of matter
A
- all substances are made up of particles
- particles are always in motion
- there are forces of attraction between particles
- there is empty space between particles
4
Q
When you heat a solid it becomes a liquid - expansion
A
- the motion increases
- weaker forces and more space
5
Q
cooling down.. - contraction
A
- motion slows down
- forces of attraction are stronger
- less space
6
Q
Chemical reactions
A
When a new substance is formed
- they are irreversible
- a new substances
7
Q
Signs of chemical reactions
A
- gas evolves
- change in temp, colour, texture
- solid is formed
- flames/ light is produced
8
Q
signs of a physical change
A
- reversible
- change of state
- mixing substances together
- change of shape
- expansion and contraction
