Do all substances change from solid to liquid and liquid to gas on heating ? Explain.

Liquid and solid halogens are

Can you think of any material other than ice that goes from solid to liquid, liquid to gas (vapour) ?

What is the reason for a substance to change from solid to liquid state ?

.............. is the amount of heat energy required to change 1 kg of solid into liquid at its melting point.

HF is a liquid while HCl is a gas - explain.

Is rubber band solid or liquid ? why?

Hot liquids flow faster than cold liquids. Explain.