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Test 3
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97
Chemistry
Undergraduate 1
11/17/2009

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Term
properties of gas
Definition
expand to fill container and its shape, low density, compressible, mixtures are homogeneous, fluid
Term
structure of gas
Definition
composed of particles traveling very fast, move in straight lines until encountering either wall or another particle
Term
kinetic molecular theory
Definition
gas particles are constantly moving, attraction between particles is negligible, particle bounce off each other and continue moving (elastic collisions), large empty space between particles, average kinetic energy of particle is directly proportional to kelvin (in temp, in speed)
Term
gas particle pushing
Definition
gas molecules constantly in motion, when strike a surface they push that surface, force exerted by gas molecules hitting the entire surface at one instant = pressure that gas is exerting
Term
pressure
Definition
the result of the constant collision between atoms or the molecule in a gas and the surfaces around them. pressure = force/area
Term
effects of gas pressure
Definition
gas will flow from high to low pressure, if somethings in its pas it will try to push it along (wind)
Term
pressure of gas depends on..
Definition
number of gas particles in a given volume, volume of the container, average speed of the particles (depended on temperature)
Term
air pressure
Definition
atmosphere exerts a pressure on everything (average 14.7 psi)
Term
barometer
Definition
column of mercury supported by air pressure, force of the air on the surface of the mercury balanced by the pull of gravity on the column of mercury, evangelista torricelli
Term
atmospheric pressure vs altitude
Definition
high up means lower atm pressure, rapid changes in pressure causes ears to pop cause of imbalance of pressure
Term
boyle's law
Definition
at constant mass and temperature, volume is inversely proportional to pressure, PV=constant
Term
standard conditions
Definition
standard pressure = 1.00 atm; standard temperature = 0C=273K; STP= standard temperature and pressure
Term
charles' law
Definition
volume is directly proportional to temperature (kelvins) V1/T1=V2/T2
Term
gay-lussac's law
Definition
pressure is directly proportional to temperature (kelvins) P1/T1=P2/T2
Term
absolute zero
Definition
the theoretical temperature at which gas would have zero volume and no pressure 0 Kelvin, never attainable
Term
combined gas law
Definition
law that predicts what happens when the volume of a sample of gas when both the pressure and temperature change P1V1/T1=P2V2/T2
Term
avogadro's law
Definition
volume is directly proportional to the number of gas molecules, equal volumes of gases contain equal numbers of molecules, V1/n1=V2/n2
Term
ideal gas law
Definition
use when you have a gas whose condition is changing PV=nRT
Term
molar mass of gas
Definition
mass in grams/moles
Term
partial pressure
Definition
each gas in the mixture exerts a pressure independent of the other gases in the mixture, sum of all the partial pressures of all the gases in a mixture equal the total pressure
Term
finding partial pressure
Definition
multiply the total pressure of the mixture by the fractional composition of the gas
Term
hypoxia
Definition
oxygen starvation leads to unconsciousness and death
Term
oxygen toxicity
Definition
to much oxygen leads to muscle spasms, tunnel vision, and convulsions
Term
nitrogen narcosis (rapture of the deep)
Definition
to much nitrogen
Term
heliox
Definition
mixture of helium and oxygen
Term
vapor pressure
Definition
partial pressure of the water vapor
Term
molar volume
Definition
there is so much empty space between molecules in the gas state that the volume of the gas is not effected by the size of the molecules (under ideal conditions)
Term
properties of liquids
Definition
high densities compared to gases, fluid, takes shape of container, keep volume (doesn't expand), cannot be compressed
Term
properties of solids
Definition
high densities, nonfluid, keep their own shape and volume, cannot be compressed
Term
crystalline solids
Definition
particles arranged in an orderly geometric pattern
Term
amorphous solids
Definition
particles do not show a regular geometric pattern over a long time
Term
melting
Definition
solid -> liquid, adding heat energy increases kinetic energy of molecules and then overcomes attractive forces holding them.
Term
boiling
Definition
liquid -> gas, adding heat increases kinetic energy, soon overcomes attractive forces
Term
surface tension
Definition
liquids tend to minimize their surface area and resists penetration. the stronger attractive force between molecules, the larger surface tension
Term
viscosity
Definition
the resistance of a liquid's flow because of strong attractive forces
Term
evaporation
Definition
the process of molecules of a liquid breaking free from the surface, physical change from liquid -> gas (vapor)
Term
factors effecting rate of evaporation
Definition
volatile liquids that evaportate quickly, nonvolatile liquids do not evaporate quickly, increasing SA increases evaporation, increasing temperature increases rate, weaker attractive forces means faster rate
Term
condensation
Definition
gas -> liquid, the vapor molecules may eventually bump into and stick to the surface of the contain or get recaptured b the liquid
Term
dynamic equilibrium
Definition
opposite processes that occur at the same rate in the same system
Term
vapor pressure
Definition
the partial pressure exerted by the vapor, depends on temperature and strength of intermolecular attractions
Term
boiling
Definition
the temperature is high enough for molecules in the interior of the liquid to escape
Term
boiling point
Definition
the temperature at which the vapor pressure of the liquid is the same as the atmospheric pressure (1 atm)
Term
endothermic
Definition
process in which heat flows into a system from the surroundings and causes surroundings to cool (evaporation), solids melting
Term
exothermic
Definition
process in which heat flows out of a system into the surroundings and warms the surroundings (condensation), liquids freezing
Term
heat of vaporization
Definition
the amount of heat needed to vaporize one mole of a liquid, endothermic, depends on the initial temperature
Term
melting point
Definition
you heat a solid, its temperature increases until it reaches the point, latent heat fusion
Term
heat of fusion
Definition
the amount of heat needed to melt one mole of a solid
Term
sublimation
Definition
a physical change in which the solid form changes directly to the gaseous form, skipping liquid form, endothermic
Term
effect if the strength of intermolecular attractions on properties
Definition
stronger attractions take more energy to separate, stronger attractions have higher boiling, melting points, and heat vaporization
Term
why are molecules attracted to each other
Definition
+ion and -ion, + - end of polar molecules, larger charge = stronger attraction
Term
dispersion forces (london forces,instantaneous dipoles)
Definition
caused by distortion in the electron cloud of one molecule inducing distortion in the electron cloud on another and can lead to a temporary dipole and leads to attractions between molecules
Term
strength of dispersion force
Definition
how easily electrons can move, or be polarized, the more electrons and the farther they are from the nuclei, the larger the dipole that can be includes. larger molecules = larger forces
Term
permanent dipoles
Definition
a separation of charge resulting from the unequal sharing of electrons between atoms
Term
dipole-dipole attraction
Definition
polar molecules have a permanent dipole, the + end of one molecule will be attracted to the - end of another
Term
intermolecular attraction and properties
Definition
all molecules are attracted by dispersion forces, polar molecules are attracted by dipole-dipole attractions and have a strong attraction then nonpolar molecules
Term
attractive forces and properties (solubility and miscibility)
Definition
like dissolves like, polar molecules dissolve in polar solvents, nonpolar molecules dissolve in nonpolar solvents, if has both polar and nonpolar ten hydrophilic-hydrophobic competition
Term
immiscible liquids
Definition
when liquid pentane, a nonpolar substance, is mixed with water, a polar substance, the two liquids separate because they are more attracted to their own kind of molecule than to the other
Term
hydrogen bonding
Definition
HF,OH,NH have strong intermolecular bonds, high melting, boiling, and solubility. when it loses the electron the nucleus becomes dishielded, and the exposed proton acts as a very strong center of positive charge
Term
H-bonds vs. chemical bonds
Definition
hydrogen bonds are not chemical bonds, hydrogen bonds are attractive forces between molecules, chemical bonds are attractive forces that make molecules
Term
crystalline solids
Definition
molecular crystalline solids, ionic crystalline solids, and atomic crystalline solids
Term
ionic crystalline solids
Definition
solids whose composite units are formula units, the smallest electrically neutral collection of cations and anions that compose the compound, higher melting point
Term
molecular crystalline solids
Definition
solids whose composite units are molecules, low melting
Term
atomic crystalline solids
Definition
covalent (effectively one giant molecule), metals (islands of cations in a sea of electrons)
Term
water (unique and important)
Definition
all three states on earth, most common solvent, supports life, liquid at room temperature, high boiling point, expands when freeze
Term
solute
Definition
the dissolved substance (minority)
Term
solvent
Definition
the substance solute dissolved in (majority)
Term
aqueous solutions
Definition
solutions in which the solvent is water
Term
soluble
Definition
when one substance (solute) dissolves in another (solvent)
Term
insoluble
Definition
when one substance does not dissolve in another
Term
solvation
Definition
when matericals dissolve, the solvent molecules surround the solvent particles due to the solvent's attractions for the solute
Term
miscible
Definition
two liquids that are mutually soluble
Term
solubility
Definition
the maximum amount of solute that can be dissolved in a given amount of solvent, concentration
Term
saturated
Definition
the maximum amount of solute that will dissolve in that solvent at that temperature
Term
unsaturated
Definition
can dissolve more solute
Term
super saturated
Definition
holding more solute than they should be able to at that temperature, unstable, precipitate
Term
electrolytes
Definition
substances whose aqueous solutions is a conductor of electrivity
Term
strong electrolytes
Definition
all the electrolyte molecules are dissociated into ions
Term
nonelectrolytes
Definition
none of the molecules are dissociated into ions
Term
weak electrolytes
Definition
a small percentage of the molecules are dissociated into ions
Term
solubility of liquid vs temperature
Definition
high temp = high sol, low temp = low sol
Term
purifying solids: recrystallization
Definition
when a solid precipitates from a solution, crystals of the pure solid form b arranging the particles in a crystal lattice because it reject impurities. make a saturated solution of it at high temperatues and then it cools and the precipitated solid will have much less impurity than before
Term
solubility of gas vs temperature
Definition
many gases dissolve in water, solubility of gas in a liquid decreases as the temperature increases
Term
solubility of gas vs pressure
Definition
directly proportional to its partial pressure, solubility of a gas in a liquid increases as the pressure increases, high pressure = high solubility
Term
dilute
Definition
low amounts of solute per amount of solution
Term
concentrated
Definition
high amounts of solute per amount of solution
Term
mass percent
Definition
the sum of the masses of solute and solvent, [mass solute (g)/mass of solution (g)] x 100%
Term
preparing a solution
Definition
need to know the amount of solution and the concentration of solution you want to prepare
Term
solution concentration molarity
Definition
moles of solute per 1 liter of solution, describes how many molecules of solute in each liter of solution, molarity = mole of solute/liters of solution
Term
dilution formula
Definition
Concentration x Volume=Concentration x Volume
Term
colligative property
Definition
any solution property whose value depends only on the number of dissolved solute particles (freezing point, boiling point, osmotic pressure of a solution)
Term
molarity
Definition
moles of solute per 1 kilogram of solvent, moles of solute/kg of solvent
Term
freezing point depression
Definition
the freezing point of a solution is always lower than the freezing point of a pure solvent
Term
molal concentration (freezing)
Definition
the difference between the freezing points of the solution and pure solvent is directly proportional, ΔTf=m*Kf
Term
boiling point elevation
Definition
the boiling point of a solution is always higher than the boiling point of a pure solvent
Term
molal concentration (boiling)
Definition
the difference between the boiling point of the solution and pure solvent is directly proportional, ΔTb=m*Kb
Term
osmosis
Definition
the process in which solvent molecules pass through a semipermeable membrane that does not allow solute particles to pass
Term
osmotic pressure
Definition
pressure that is needed to prevent osmotic flow of solvent
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