2.3 Changes in arrangement

Question 1

Melting and boiling point

Answer 1

At a substance’s melting point, it will begin to melt or will freeze if energy is transferred to the surroundings.

At a substance’s boiling point, it will begin to boil or condense depending on if energy is transferred to the particles or the surroundings.

A substance can evaporate if particles have high enough energy and leave the surface of the liquid.

Question 2

Particle theory

Answer 2

The amount of energy needed to change state depends on the strength of the forces between the particles of the substance.

The nature of particles depends on the type of bonding and the structure of the substance.

The stronger the forces the higher the melting and boiling point of the substance.