Kinetic Molecular Theory

Question 1

Solids

Answer 1

• Have a definite shape and volume
• Crystalline solids (e.g. salts & diamond) have their particles arranged in a regular, repeating pattern.
• Solids that do not have this regular structure are called amorphous solids e.g. glass, rubber

Question 2

Particles of a solid

Answer 2

• are able to vibrate, although they are not able to move out of their fixed position.
• have little kinetic energy.
• have high attraction between particles.

Question 3

Liquids

Answer 3

• Have a definite volume, take the shape of the container and their surfaces are always horizontal.
• Particles are further apart than those in a solid and are in constant motion, showing vibrational, rotational and translational movement. Thus liquids can flow.
• Particles have a higher amount of kinetic energy.

Question 4

Gases

Answer 4

• Take the same shape and volume as the container they are in.
• Particles are free to move in any direction and have vibrational, rotational and translational movement.
• Particles have the highest amount of kinetic energy
• There is little attraction between particles

Question 5

Plasma, the fourth state of matter

Answer 5

• Hydrogen nuclei and electrons

- Stars are made of plasma, so plasma is the most abundant form of matter in the universe.

Question 6

Changes in state

Question 7

The causes of changes in state: increase in temperature

Answer 7

• When substances are heated the heat energy is converted into kinetic energy.
• Particles are able to overcome the forces of attraction between each other.
• Particles are able to move faster – generally means that particles take up a greater space.

Question 8

The causes of changes in state: decrease in temperature

Answer 8

• When substances are cooled their particles slow down – decrease kinetic energy.
• The attraction between particles is greater, holding the particles closer together.