Question

dentify the examples of diffusion in the list below. Check all that apply.

A teacher takes the cap off a permanent marker. A few minutes later, students at the back of the classroom complain about the odor of the marker.

A cooking school student burns a piece of toast. Soon, the entire kitchen smells like burnt toast.

An inflated balloon shrinks when it is placed in a cold freezer.

Toxic fumes produced by a chemical factory are detected in the air in a town several miles away.

Heating a flexible container filled with gas causes it to expand.

Answer 1

Diffusion examples: the 1st, 2nd, and 4th.

- Teacher takes cap off marker → odor molecules spread from a high-concentration source through the air (diffusion, aided by air currents).
- Burnt toast → smell molecules spread through the kitchen by diffusion (and convection).
- Toxic fumes detected miles away → the fumes spread out from the source (molecular diffusion plus bulk transport by wind); qualifies as diffusion-driven mixing.

Not diffusion:
- Balloon shrinks in a cold freezer → mainly gas contraction with decreasing temperature (PV = nRT); not diffusion (unless gas leaks through the latex, which isn’t stated).
- Heating a flexible container → expansion of the gas due to temperature increase (thermal expansion/pressure change), not diffusion.