Nothing happens to these particles when it comes to size however if it were to be speed, the sample would increase. Fact: The size of a particle will never change!
Explanation: When a sample liquid is heated in a closed container, the temperature increases and thereby increasing the speed of the particles which would try to escape the surface of water into the free space above the liquid. This process is known as Vaporization and since its a closed container, it will take the form of the condensed vapors on the surface lid of the container.
Thus in no process would the size of the particle change as temperature affects only the speed of the container, not the size of the particles.
