A liquid is left in an open dish. After several days, there is less liquid in the dish. Which of the following statements explains this observation? The
-
most energetic molecules leave the surface and escape into the air.
- least energetic molecules leave the surface and escape into air.
- most energetic molecules leave the surface and return.
- least energetic molecules leave the surface and return.
The correct answer is: A
Explanation
The statement that explains the observation is:
The most energetic molecules leave the surface and escape into the air.
This phenomenon is known as evaporation. In a liquid, molecules have varying energies, and the molecules with higher kinetic energies (the most energetic ones) are more likely to overcome the attractive forces within the liquid and transition into the gaseous phase. These molecules escape from the surface of the liquid into the air, gradually reducing the amount of liquid in the open dish. Evaporation is a process that occurs continuously as long as there is a liquid exposed to the air.