Explain why, we can easily move our hand in air but to do the same through a plank of wood, we need a karate expert.

When a gas jar containing air is inverted over a gas jar containing bromine vapour, the red-brown bromine vapour diffuse into air. Explain how bromine vapour diffuse into air.

Describe in your own words, what happens to the particles when salt dissolves in water.

Give one example of the diffusion of a solid in another solid.

Explain why, the diffusion of a solid in another solid.