 | Term | Definition |
| |
amorphous solid |
a solid in which particles are not arranged in a regular, repeating pattern that often is formed when molten material cools too quickly to form crystals |
| |
atmosphere |
the unit that is often used to report air pressure |
| |
barometer |
an instrument that is used to measure atmospheric pressure |
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boiling point |
the temperature at which a liquid’s vapor pressure is equal to the external or atmospheric pressure |
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condensation |
the energy-releasing process by which a gas or vapor becomes a liquid |
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crystalline solid |
a solid whose atoms, ions, or molecules are arranged in an orderly, 3-D structure; can be classified by shape and composition |
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Dalton's Law of Partial Pressures |
states that the total pressure of a mixture of gases is equal to the sum of the pressures of all the gases in the mixture |
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deposition |
the energy-releasing process by which a substance changes from a gas or a vapor to a solid without first becoming a liquid |
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diffusion |
the movement of one material through another from an area of higher concentration to an area of lower concentration |
| |
dipole-dipole forces |
the attractions between oppositely charged regions of polar molecules |
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dispersion forces |
the weak forces resulting from temporary shifts in the density of electrons in electron clouds |
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elastic collision |
describes a collision in which kinetic energy may be transferred between the colliding particles but the total kinetic energy of the 2 particles remains the same |
| |
evaporation |
the process in which vaporization occurs only at the surface of a liquid |
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freezing point |
the temperature at which a liquid is converted into a crystalline solid |
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Graham's Law of Effusion |
states that the rate of effusion for a gas is inversely proportional to the square root of its molar mass |
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hydrogen bond |
a strong dipole-dipole attraction between molecules that contain a hydrogen atom bonded to a small, highly electronegative atom with at least one lone electron pair |
| |
kinetic-molecular theory |
explains the properties of gases in terms of the energy, size, and motion of their particles |
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melting point |
for a crystalline solid, the temperature at which the forces holding a crystal lattice together are broken and it becomes a liquid |
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pascal |
the SI unit of pressure; one pascal (Pa) is equal to a force of one Newton per square meter |
| |
phase diagram |
a graph of pressure versus temperature that shows which phase a substance exists in under different conditions of temperature and pressure |
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pressure |
force applied per unit of area |
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sublimation |
the energy-requiring process by which a solid changes directly to a gas without first becoming a liquid |
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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 |
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surfactant |
a compound, such as soap, that lowers the surface tension of water by disrupting hydrogen bonds between water molecules; also called a surface active agent |
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temperature |
a measure of the average kinetic energy of the particles in a sample of matter |
| |
triple point |
the point on a phase diagram representing the temperature and pressure at which the 3 phases of a substance (solid, liquid, gas) can coexist |
| |
unit cell |
the smallest arrangement of connected points that can be repeated in 3 directions to form a crystal lattice |
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vaporization |
the energy-requiring process by which a liquid changes to a gas or vapor |
| |
vapor pressure |
the pressure exerted by a vapor over a liquid |
| |
viscosity |
a measure of the resistance of a liquid to flow, which is affected by the size and shape of the particles, and generally increases as the temperature decreases and as intermolecular forces increase |
