Term | Definition |
gases | contain particles that are far apart, in random motion, and independent of one another |
solids | contain particles very close in space and maintain a rigid shape; significant attractive forces exist between particles. |
liquids | intermediate between gases and solids |
evaporation or vaporization | escape of molecules from the liquid to the gas phase |
condensation | when molecules from the liquid phase can escape to the vapor phase through evaporation, molecules in the gas phase can strike the surface of the liquid and return to the liquid phase. |
vapor pressure | pressure exerted by a vapor in equilibrium with its liquid phase. |
volatile liquids | very weak attractive forces between molecules; evaporate very rapidly at ambient temperature and have high vapor pressures as a result. |
cohesive forces | exist between water molecules in a liquid. |
adhesive forces | exist between water molecules and the walls of the container |
convex | adhesive forces < cohesive forces |
concave | adhesive forces > cohesive forces |
normal boiling point | temperature when the vapor pressure is 1 atm |
water | 100 ºC |
ether | 35 ºC |
ethyl alcohol | 78 ºC |
freezing/melting point | the temperature at which the solid phase of a substance is in equilibrium with its liquid phase. |
heat of fusion | energy required to change 1 g of a solid at its melting point to a liquid |
heat of vaporization | energy required to change 1 g of a liquid to vapor at its normal boiling point |
ice melts | total energy = mass x heat of fusion |
liquid water is warmed from 0° to 100°C | energy = mass x specific heat x ΔT |
water evaporates | energy = mass x heat of vaporization |
hydrogen bonds | one type of strong intermolecular force/attraction between molecules |
london forces | arise from uneven, instantaneous charge distributions due to electron movement in nonpolar molecules. |
hydrates | are solids that contain water molecules as part of their crystalline structure |
% water | mass water/molar mass x 100 |
osmosis | process by which water flows through a membrane from a region of more pure water to a region of less pure water |
reverse osmosis | process by which water flows through a membrane from a region of less pure water to a region of more pure water, due to the presence of an external stimulus (typically pressure) |