atoms

Question 1

what is diffusion

Answer 1

diffusion is the movement of particles from a region where they are of high concentration to low

Question 2

diffusion in gases

Answer 2

diffusion in gases is quick because the particles in a gas move more quickly (it happens even faster in hot gases)

Question 3

diffusion in liquids

Answer 3

diffusion can also happen in liquids. this is because the particles in liquids can move around each other, which means that they are eventually evenly mixed. diffusion in liquids is slower than in gases because the particles have less energy / move more slowly

Question 4

diffusion in solids

Answer 4

diffusion doesn’t happen at all in solids because the particles in a solid can only vibrate on the spot, rather than moving from place to place

Question 5

describe a diffusion experiment

Answer 5

Hydrochloric acid is placed at one end of a tube, ammonia solution at the other. Where they meet a ring of ammonium chloride appears. The diagram shows it is closer to the HCL end. From this we can tell that ammonia must have travelled faster, as it got further in the time. Lighter particles travel faster - so we can tell that ammonia is a lighter gas.

Question 6

describe a dilution experiment

Answer 6

Put a coloured substance in a solvent e.g food colouring in water. You can see that over time the colour levels out but is weaker than the original colour - this is dilution. Dilution at different temperatures: more heat; means more energy; means more movement; so the particles can move to different areas more quickly. So applying heat decreases the amount of time taken for the coloured substance to be fully diluted.