Chapter 12- Liquids Solids and Gases – Flashcards
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| Liquids |
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| particles are in constant motion, but closer together and lower in kinetic energy than those in a gas |
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| liquids |
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| attraction between _____ particles is caused by intermolecular forces |
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| london dispersion |
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| _______ is the weakest intermolecular force |
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| dipole-dipole |
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| are stronger intermolecular forces than london dispersion |
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| hydrogen bonding |
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| ______ is the strongest intermolecular force |
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| fluids |
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| since particles are not fixed, they move around constantly; they are referred to as _________ |
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| they diffuse and evaporate because they have more kinetic energy than others and escape |
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| Use the kinetic molecular theory to explain why liquids are fluids (why they diffuse and evaporate) |
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| liquids |
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| _________ have high densities compared to gases because of the close arrangement of liquid particles |
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| liquids |
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| ________ are less compressible than gases because liquid particles are more closely packed together |
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| liquids |
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| diffusion is slower in ____ than in gases because particles are closer together and their attractive forces between particles is greater |
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| liquids |
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| in _________, molecules pull together to minimize the size |
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| surface tension |
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| ___ is the force that pulls adjacent parts of a liquids surface together, decreasing surface area to the smallest possible size. (it results from the attractive forces between particles of a liquid |
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| capillary action |
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| the attraction of the surface of a liquid to the surface of a solid |
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| vaporization |
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| the process by which a liquid of solid changes to a gas |
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| fact |
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| to go from liquid or solid to a gas, you add heat |
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| evaporation |
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| the process by which particles escape from the surface of a nonboiling liquid and enter the gas state |
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| evaporation |
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| occurs because the particles of a liquid have different kinetic energies |
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| evaporation |
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| some particles with higher than average energies can overcome intermolecular forces holding them together and can then escape into the gas state |
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| freezing or solidification |
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| physically changing liquid to solid by removing heat is called _____ |
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| viscosity |
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| is the resistance of a substance to flow |
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| solids |
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| intermolecular forces hold particles in fixed positions with only vibrational movement around fixed points |
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| crystalline solids |
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| contain crystals in which the particles are arranged in an orderly, geometric, repeating pattern |
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| amorphous solid |
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| particles are arranged randomly |
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| solids |
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| ______- have a definite shape and volume |
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| melting |
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| the physical change of a solid to a liquid by the addition of heat |
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| melting point |
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| temperature where kinetic energy within the solid overcome the attractive forces holding them together |
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| physical change |
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| same particles into a different form |
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| solids |
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| have a definite melting point |
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| crystalline solids |
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| _________, which have a definite melting point, particles can break out of a fixed position |
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| amorphous solids |
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| _______, such as glass and plastics, they have no definite melting point, and are able to glow over a wide range of temperatures |
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| supercooled liquids |
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| amorphous solids are sometimes classified as __________ because they have the ability to flow over a range of temperatures. (these properties exist because their particles are arranged randomly, much like those in a liquid) |
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| solids |
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| _____ are slightly denser than liquids and much denser than gases because the particles of a solid are more closely packed than that of a gas or liquid |
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| solids |
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| _____ are less compressible than liquids |
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| solids |
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| in _______, the rate of diffusion is millions of times slower than in liquids |
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| crystal structure |
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| the total three dimensional arrangement of particles of a crystal |
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| lattice |
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| the arrangement of particles can be represented by a coordinate system called a _____ |
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| unit cell |
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| the smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire lattice is called the _______ |
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| ionic crystals |
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| consist of positive and negative ions arranged in a regular pattern |
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| ions |
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| can be monatomic or polyatomic |
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| ionic crystals are arranged in a regular pattern. in metallic crystals, the metal atoms are surrounded by a sea of valence electrons |
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| Distinguish between ionic crystals and metallic crystals |
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| covalent network crystals |
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| occur when covalent bonding extends throughout a network that includes a very large number of atoms (ex. diamond, quartz) |
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| covalent network crystals |
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| essentially giant molecules |
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| metallic crystals |
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| occur when metal atoms are surrounded by a sea of valence electrons, which are donated by the metal atoms and belong to the crystal as a whole |
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| high electric conductivity |
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| the freedom of the valence electron to move throughout the crystal explains the high ___________ |
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| covalent molecular crystals |
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| consist of covalently bonded molecules held together by intermolecular forces * if nonpolar, the only forces are london dispersion * if polar, the molecules are held together by weak london dispersion forces, stronger dipole-dipole forces, and stronger hydrogen bonding. *these are much weaker than intramolecular covalent bonds |
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| Ionic covalent network metallic covalent molecular |
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| *hard and brittle; good insulator *high melting point; hard *good conductor *soft |
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| Equilibrium |
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| a dynamic condition in which two opposing changes occur at equal rates in a closed system |
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| equillibrium |
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| when two opposing things happen at the same rate |
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| closed system |
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| matter cannot enter or leave, but energy can |
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| condensation |
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| the process by which a gas changes to a liquid |
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| Le Chatelier's Principle |
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| states that when a system at equilibrium is disturbed by application of a stress, it attains a new equilibrium position that minimizes stress |
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| equilibrium vapor pressure |
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| the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature |
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| equilibrium vapor pressure |
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| increases with increasing temp because increasing the temp of a liquid increases the average kinetic energy |
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| volatile liquids |
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| liquids that evaporate quickly and have relatively weak forces of attraction between particles |
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| boiling |
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| the conversion of a liquid to a vapor within the liquid as well as its surface |
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| boiling |
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| __________ occurs when the equilibrium vapor pressure of the liquid equals the atm pressure which is the boiling point |
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| molar heat of vaporization |
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| the amount of heat energy needed to vaporize one mole of a liquid at its boiling point |
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| fact |
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| boiling is throughout the whole thing. evaporation is layers at a time |
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| molar heat of vaporization |
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| 40.79 KJ/mol |
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| heat of vaporization |
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| the stronger the attraction between the particles of a liquid, the more energy required to overcome it which results in a higher _____________ |
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| freezing point |
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| the temp at which the solid and liquid are in equilibrium at 1 atm pressure (760 torr, 101.25 kPa) |
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| molar heat of fusion |
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| the amount of energy required to melt one mol of a solid at its melting point |
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| molar heat of fusion |
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| 6.009 KJ/mol |
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| sublimation |
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| the change of state from a solid directly to a gas (dry ice) |
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| deposition |
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| the change of a state from a gas to a solid (frost) |
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| phase diagrams |
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| graphs of pressure vs temp that shows the conditions at which phases of a substance exists |
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| triple point |
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| indicates the temp and pressure conditions at which the solid, liquid, and vapor of a substance can coexist at equilibrium |
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| critical point |
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| indicates the critical temp and pressure |
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| critical temperature |
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| temp above which the substance cannot exist in the liquid states |
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| critical pressure |
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| the lowest pressure at which the substance can exist as a liquid at critical temp |
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| fact |
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| critical pressure of water is 217.75 atm critical temp of water is 373.99 C |
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| the structure of water |
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| two atoms of hydrogen and one atom of oxygen united by polar covalent bonds. A water molecule is bent |
