I. change of state II. Diffusion III. Radiation IV. Osmosis which of the processes above can be explained using the kinetic theory?

Analyze the question: We need to decide which of the four processes can be explained by the kinetic theory of matter, which says matter is made of tiny particles in constant random motion, with the energy and speed of the particles depending on temperature.

Concept: Kinetic theory explains things that involve the movement or arrangement of particles (molecules).

Checking each process:

• I. Change of state (melting, boiling, etc.): Yes. Adding or removing heat changes the particles' kinetic energy and how strongly they are held together, so solids become liquids and liquids become gases.
• II. Diffusion: Yes. Particles move randomly and spread from regions of high concentration to regions of low concentration.
• III. Radiation: No. Heat transfer by radiation happens through electromagnetic waves and needs no particles or medium. It travels through a vacuum (e.g. sunlight reaching Earth), so kinetic theory does not explain it.
• IV. Osmosis: Yes. It is the movement of solvent (water) molecules through a semi-permeable membrane, which is a result of random molecular motion, much like diffusion.

So the processes explained by kinetic theory are I, II and IV.

Answer: Option D.

Tip: Remember that radiation is the odd one out. Any time you see "radiation" in a kinetic theory question, cross it out, because it involves waves and not particle motion. Conduction, convection, diffusion, osmosis, Brownian motion, evaporation and gas pressure are all kinetic theory topics.