| A | B |
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| Kinetic molecular theory | explains the properties of gases in terms of the energy, size and motion of their particles |
| elastic collision | describes a collision in which kinetic energy may be transferred between the colliding particles but the total kinetic energy of the two particles remains the same |
| temperature | a measure of the average kinetic energy of the particles in a sample of matter |
| pressure | force applied per unit area |
| viscosity | a measure of the resistance of a liquid to flow |
| surface tension | the energy required to increase the surface area of a liquid by a given amount; results from an uneven distribution of attractive forces |
| surfactant | a compound that lowers the surface tension of water by disrupting hydrogen bonds between water molecules |
| crystalline solid | a solid whose atoms, ions, or molecules are arranged in an orderly, geometric, three-dimensional structure |
| unit cell | the smallest arrangement of connected points that can be repeated in three directions to form a crystal lattice |
| amorphous solid | a solid in which particles are not arranged in a regular, repeating pattern that often is formed when motlen material cools too quickly to form crystals |
| melting point | the temperature at which forces are broken and a solid becomes a liquid |
| vaporization | the energy requiring process by which a liquid changes to a gas or vapor |
| evaporation | the process in which vaporization occurs only at the surface of a liquid |
| vapor pressure | the pressure exerted by a vapor over a liquid |
| boiling point | the temperature at which a liquid's vapor pressure is equal to the external or atmospheric pressure |
| sublimation | the energy requiring process by which a solid changes directly to a gas without first becoming a liquid |
| condensation | the energy releasing process by which a gas or vapor becomes a liquid |
| deposition | the energy releasing process by which a substance changes from a gas or vapor to a solid without first becoming a liquid |
| freezing point | the temperature at which a liquid is converted into a solid |
| phase diagram | a graph of pressure versus temperature that shows which phase a substance exists in under different conditions of temperature and pressure |
| triple point | the point on a phase diagram representing the temperature and pressure at which the three phases of a substance (solid, liquid and gas) can coexist |
| physical change | a type of change that alters the physical properties of a substance but does not change its composition |
| chemical change | a process involving one or more substances changing into new substances |
| law of conservation of mass | states that mass is neither created nor destroyed during a chemical reaction but is conserved |
| substance | a form of matter that has a uniform and unchanging composition |
| physical property | a characteristic of matter that can be observed or measured without changing the sample's composition |
| extensive property | a physical property, such as mass, length and volume, that is dependent upon the amount of the substance presen |
| intensive property | a physical property that remains the same no matter how much of a substance is present |
| chemical property | the ability or inability of a substance to combine with or change into one or more new substances |
| states of matter | the physical forms in which all matter naturally exists on Earth |
| solid | a form of matter that has its own definite shape and volume |
| liquid | a form of matter that flows, has a constant volume, but indefinite shape |
| gas | a form of matter that has an indefinite volume and indefinite shape and can be compressed easily |
| vapor | gaseous state of a substance that is a liquid or a solid at room temperature |
