Evaporating, boiling and condensing

你需要知道的

• Particles have kinetic energy because they move, and potential energy because of the forces between them.
• Internal energy is the total kinetic and potential energy of all the particles in a system.
• Heating raises the internal energy and can cause melting and boiling; cooling lowers it and causes condensing and freezing.
• In a change of state mass is conserved, and the change is physical, so it can be reversed.
• Evaporation happens only at the surface, where some particles have enough energy to escape.

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