Please help me with this Chemistry question. How do substances go from one state of matter to another? (Discuss in terms of energy).

Answer 1

They change state by either absorbing or releasing energy without any change in temperature. All of the energy either absorbed or released is used to change the phase (state) and therefore the temperature does not change during a phase transition.

For example, to go from solid H2O (ice) to liquid H2O, energy must be added to the ice. All of the energy added goes into breaking the bonds that hold the ice together as a solid and turning into liquid, but the temperature remains at 0ºC, so there is no change in temperature.