Question

How does increasing the heat energy of a substance change the behavior of particles of the substance?

Answer 1

Kinetic theory of matter: All matter is made up of atoms and molecules that are constantly moving.

When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.



Solid at Different Temperatures

 

 

 

 

Mass of the object remains the same, however. Solids, liquids and gases all expand when heat is added. When heat leaves all substances, the molecules vibrate slower. The atoms can get closer which results in the matter contracting. Again, the mass is not changed.