Chemistry 0620 · IGCSE · Diffusion

Diffusion — practice question

Tiny crystals of purple $\text{KMnO}_4$ ($M_r = 158$) and orange $\text{K}_2\text{Cr}_2\text{O}_7$ ($M_r = 294$) were put at the centres of separate petri dishes containing agar jelly. They were then left under identical physical conditions. After a period of time, the colour from each substance had spread out as shown. The arrow lengths show the comparative distances moved by particles of each substance. Which statement is correct?

  • ADiffusion is faster in dish 1 because the mass of the particles is greater.
  • BDiffusion is faster in dish 2 because the mass of the particles is greater.
  • CDiffusion is slower in dish 1 because the mass of the particles is smaller.
  • DDiffusion is slower in dish 2 because the mass of the particles is greater.

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