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53 Cards in this Set
- Front
- Back
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solution
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homogenous mixture of two or more compounds in a single phase such as solid liquid or gas
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solvent
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compound which there is more of in a solution
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solute
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compound which there is less of in a solution
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ideal solutions
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compounds can be interchanged within the solution without changing the spatial arrangement of molecules
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ideally dilute solutions
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solute molecules are completely separated y solvent molecules so that they have no interaction with each other
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colloids
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-liek a solution only the solute particles are larger
-colloid particles are usually too small to be filtered but large enough to be separated by semipermeable membrane (dialysis) -colloidal suspensions will scatter light unlike a true solution (Tyndall effect) -may be attracted (lyophillic) or repelled (lyophobic) by their dispersion medium |
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Like dissolves like
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polar dissolves polar,
nonpolar dissolves nonpolar |
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London dispersion forces
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forces responsible for nonpolar molecules held together by weak intermolecular bonds resulting in instantaneous dipole movements (induced dipoles)
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Solvation
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when ionic compounds dissolve and break up into cations and anions and are surrounded by charged ends of polar solvent
(H20 is good polar solvent) |
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Hydration
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when several water molecules attach to one side of ionic compound and break ionic bond, molecules are now in aqueous phase
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Nitrite
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N02 -
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nitrate
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NO3 -
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Sulfite
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SO3 2-
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Sulfate
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SO4 2-
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hypochlorite
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ClO-
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chlorite
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ClO2 -
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Chlorate
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ClO3 -
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Perchlorate
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ClO4-
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Carbonate
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CO3 2-
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bicarbonate
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HCO3 -
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phosphate
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PO4 3-
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electrolyte
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a compound which forms ions in aqueous solutions and is able to conduct electricity
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Molarity M
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moles of compoud/volume of solution
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Molality m
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moles of solute/ kilograms of solvent
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mole fraction X
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moles of a compound/total moles of all species in solution
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mass percentage
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100 times ration of mass of solute to total mass of solution
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Parts per million
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10^6 times the ration of mass of solute to total mass of solution1`
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lecture question 73
What is the approximate molarity of a Nacl solution with a specific gravity of 1.006 |
specific gravity of water is 1, if it is greater than 1, then x-1 will be the mass added
so .006 kg was added, or 6 g, which is 1/10 of a mole |
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lecture question 75
which is most concentrated 1m NaCl 1M NaCl |
remember molarity is # moles over solution which is solute + solvent while molality is # moles over solvent only, so molality is less concentrated
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breaking and forming bonds
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breaking bonds requires energy (endothermic), forming bonds releases energy (exothermic)
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heat of solution
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overall change in energy of a reaction as a result of breaking and forming bonds is equal to enthalpy
negative heat of solution= stronger intermolecular bonds positive heat of solution= weaker intermolecular bonds -when solutions form entropy increases |
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vapor pressure
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-when amount of molecules moving from liquid to gas equals the amount moving from gas to liquid (equillibrium)
-related to kinetic energy of molecules thus affected by temperature -endothermic -vapor pressure = atmospheric pressure |
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Boiling
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-vapor pressure = atmospheric pressure
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Melting
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-vapor pressure of a solid equalds the vapor pressure of the liquid
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Raoults Law for nonvolatile (no vapor pressure solutes)
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Pv=XaPa
vapor pressure of slution =mole fraction of liquid a vapor pressure of liquid A |
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Raoults Law for volatile solutes
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Pv=XaPa + XbPb
each Xp term equals the partial vapor pressure |
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Deviation from Raoluts Law for non-ideal solutions
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-for nonideal solutions intermolecular forces between molecules will be changed
-for + heat of solution, weaker bonds are formed, more bonds can be broken and more molecules can escape from surface, there will be a positive deviation from raoults law -for negative heat of solution, stronger intermolecular bonds, less bonds leave surface, less vapor pressure than expected from raoluts law |
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heat of hydration
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separation of water molecules and formation of bonds between ions and water molecules
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Lecture question 83:
Vapor pressures in solutions |
Vapor pressures may be less than one of the pure liquids but not both
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Lecture Question 86: Vapor pressures in ideal solutions
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In an ideal solution, vapor pressure will be in between vapor pressures of solute and solvent
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Solubility
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solutes tendency to dissolve in a solvent,
reverse reacion: precipitation |
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saturation
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rate of dissolution is equal to rate of precipitation
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Ksp
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solubility product or equillibrium constate for equillibrium of solvation
-use Ksp like any other equillibrium constant equal to products over reactants (no solids or pure liquids) |
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Solubility and Solubility product
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-solubility product = ksp a constant
depends on temperature! solubility: the maximum number of moles of solute that can dissolve in solution -depends on common ions in solution and temperature |
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Using Ksp to determine solubility
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set Ksp equal to ions in solution and their respected coefficients
-assign variables as number of moles to concentration of ions in solution example: BaF2-> Ba 2+(aq) + 2F-(aq) Ksp= [Ba2+][F-]^2 ksp is given 2.4X10^-5= (x)(2x)^2 x= 1.8 x 10^-2 mol/L That is the solubility of BaF2 in one liter of water at 25 degrees C. If we add one mole of NaF it will completely dissociate to one mole Na+ one mole F-. It does not matter what order it is added.. Na+ is a spectator ion but F- causes a common ion effect pushes equillibrium to the left so BaF2 is less soluble modifly solubility equation Ksp=(x)(2x+1)^2 add +1 bc there is already 1 mole of F- from NaF -drop 2x bc it will be much less than one..and find new solubility |
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NO3- (nitrate)
NH4+ (ammonium) alkali metals |
very soluble!
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Ionic compounds with halogens Cl- Br- and I-
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Soluble
except for silver mercury and lead (Ag+, Hg2 2+, Pb2+) not soluble |
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Sulfate compounds (SO4 2-)
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soluble except for mercury lead and heavier alkaline metals
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Heavier alkaline metals (Ca2+, Sr2+, Ba2+)
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soluble when with OH or Sulfides (S2-) but not with sulfates!
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Carbonates, phosphates, sulfides, and hydroxides (CO3 2-, PO4 3-, S2-1, OH-)
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-generally insoluble except for mentioned exceptions
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Solubility Factors:
Henry's Law Vs. Rault's Law |
Henry's Law: Pv=Xaka2
Raults Law: Pv=XaPa Xa= mole fraction Pa does not equal Ka2, use each law in specific conditions Henry's Law: -relates vapor partial pressure of a gas directly proportional to its solubility -use when looking at the vapor partial pressure of a volatile solute where the solute has a low concetration -Rault's Law: most accurate when looking at the vapor partial pressure of a solvent with high concentration because in this case it behaves more like a pure substance Raults Law: high solvent conc Henry's Law: low solute concentration, vapor pressure not proportional to when it is pure!! |
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Temperature increases for solutions and other factors that affect solubility
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-solubility of salts increase as temperature increases
-solubility of gas decreases with temperature increases -gases that are larger experience greater van der waals forces and are more soluble, gases that chemically react with solvent are more soluble -low temp high pressure increases gas solubility |
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Question 86: A 25ml sample of hard water is titrated with a .001m solution of EDTA and the endpoint of the titration is reached at 50ml of EDTA addded. What is the concentration of Ca 2+ and Mg 2+
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Since its a one to one ratio in the reactoin you can:
50x.001=25x.002 |
