Practice Question

1.Define the term diffusion.

Diffusion is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.

2. Explain why diffusion occurs

At room temperature the particles in liquids or gases  have energy, so they move in random directions. 

Whilst moving the particles collide with each other and the walls of the container. 

Gradually, they spread themselves out from area of high concentration to an area of low concentration.

3. Explain the importance of diffusion to living cells

Dffusion allows cells to obtain oxygen for aerobic respiration, whilst removing harmful waste products such as carbon dioxide and urea.