Butene boils at -6 degree. Use the kinetic particle theory to explain what happens when butene boils.

The "kinetic particle theory" explains the properties of solids, liquids and gases. There are energy changes when changes in state occur.

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.

dynamic equilibrium is the answer.