| A | B |
|---|
| plasma | a state of matter that starts as a gas and then becomes ionized; it consists of free moving ions and electrons, it takes on an electric charge, and its properties differ from those of a solid, liquid, or gas. |
| energy | the capacity to do work. |
| thermal energy | the kinetic energy of a substance's atoms. |
| evaporation | the change of a substance from a liquid to a gas. |
| sublimation | the process in which a solidchanges directly into a gas or a gas changes directly into a solid. |
| condensation | the change of a substance from a gas to a liquid. |
| crystalline solid | a solid that consists of crystals. |
| kinetic energy | the energy of a moving object due to its motion. |
| heat | the energy transferred between objects that are at different temperatures; energy is always transferred from higher temperature objects to lower temperature objects. |
| endothermic change | a change that requires energy. |
| melting point | the temperature and pressure at which a solid becomes a liquid. |
| boiling point | the temperature at which a liquid becomes a gas. |
| condensation point | the temperature at which a gas becomes a liquid. |
| freezing point | the temperature at which a liquid turns into a solid. |
| amorphous solid | a solid in which the particles are not arranged with periodicity or order. |
| surface tension | the force acting on the particles at the surface of a liquid that causes a liquid to form spherical drops. |
| exothermic change | a change in which energy is released. |
