On a filter paper or a white paper napkin, use a pipette to drop 1 drop each at a considerable distance from each other

On a filter paper or a white paper napkin, use a pipette to drop 1 drop each at a considerable distance from each other: water, cologne (toilet water), ethyl alcohol. Which droplet dries faster? Which is slower? What phenomena – physical or chemical – occur in this case? The smell of cologne you feel indicates the penetration of the molecules of odorous substances that make up it, between the molecules of the gases that form the air. What is this phenomenon called?

A drop of ethyl alcohol will dry the fastest, followed by cologne, and slowest, a drop of water. This is explained by the fact that the boiling point of alcohol is lower than the boiling point of water. Cologne occupies an intermediate place, since it is a solution of water, alcohol and aromatic substances. The observed phenomenon is called evaporation, it is a physical phenomenon. The phenomenon of the penetration of odorous molecules between the molecules of gases that form the air is called diffusion.

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