Solutions Flashcards
Are all mixtures solutions?
No
Are all solutions mixtures?
Yes
When is solvation exothermic?
When the new interactions are stronger than the old ones
What kind of temperature favors solubility of gas in liquid?
Lower temp
When is solvation endothermic?
When new interactions are weaker than old
When is endothermic solvation favored?
At higher temperatures
Ideal solution
Enthalpy of the dissolution/solvation = 0
Spontaneous processes do what to Gibb’s free energy?
Reduce Gibb’s free energy
Nonspontaneous processes do what to Gibb’s free energy
Increase Gibb’s free energy
Breaking bonds is
Endothermic
Making bonds is
Exothermic
Solubility
Maximum amount of the substance that can be dissolved in a particular solvent at a given temperature
Above what solubility are solutes considered soluble?
Above 0.1 M
Solubility rules
NH4+ and Group 1 are water soluble
Nitrates and Acetates are soluble
Cl, Br, I excluding F are soluble except for Ag, Pb, Hg2
All sulfates are soluble except Ca, Sr, Ba, Pb
All metal oxides are insoluble except alkali, ammonium, CaO, SrO,BaO
All hydroxides are insoluble except for alkali metals, ammonium, Ca, Sr, Ba
Carbonates, phosphates, sulfides, sulfites are insoluble except alkali metals and ammonium
Complex ion/Coordinated compound
a molecule in which a cation is bonded to at least one electron donoor moleules called ligands
Coordinate covalent bonds
Hold complexes together where an electron donor pair (Lewis base) and acceptor (Lewis acid) form a Lewis acid-base adducts
Chelation
Central cation bonded to same ligand in multiple places in a complex
Concentration of solution after dilution
MV=MV
Normality
mols solute/kg solvent
Saturation point
Equilibrium in creating a solution where solute concentration is max for given temp and pressure
Change in free energy at equilibrium
0
Solubility product constant
Ksp
Ksp equation
Ksp=[A^n+]^m[B^m-]^n
Would a Ksp have a denominator?
No
What happens to the Ksp as temperature rises for gas solutes?
Decreases
What happens to the Ksp as temperature rises for gas solutes?
Increases
Ksp at higher pressures for gases
Larger
Ksp at lower pressures for gases
Higher
Ion product (IP)
Similar to Q
Unsaturated
IP
Supersaturated
IP>Ksp
Ksp equations used for what kind of problems?
Sparingly/insoluble
Sparingly soluble salt formula MX has what Ksp?
x^2
Sparingly soluble salt formula MX^2 has what Ksp?
4x^3
Sparingly soluble salt formula MX3
27x^4
Relative Ksp of complex?
High
Kf
Formation constant of complexes
If very high, the final concentration of the complex ion will be very near to the limiting reagent
Common ion effects
Reduced solubility due to same ion already in solution
No effect on solubility product constant, only on molar solubility of salt
Colligative properties
Dependent on the concentration of dissolved particles but not their chemical identity
Colligative property examples
Vapor pressure depression
Boiling point elevation
Freezing point depression
Osmotic pressure
Raoult’s law
Vapor pressure depression caused by solutes in solution
As solute is added to solvent, vapor pressure decreases proportionally
Raoult’s law expression
PA=XAPA not
PA=vapor pressure when solutes are present
XA=mol fraction of solvent A
PA not=vapor pressure of solvent A in pure state
Lowering of solution’s vapor pressure means
Higher boiling point
Boiling point elevation
When a nonvolatile solute is dissolved in a solvent to create a solution, boiling point greater than pure solvent
Boiling point depression
Temperature where vapor pressure of the liquid equals ambient pressure
More energy/higher temp needed to to get vapor pressure to reach ambient pressure
Boiling point depression expression
Delta(T)=iKbm
i=van’t Hoff factor=number of particles in which a compound dissociates (NaCl=2)
Kb=proportionality constant of the solvent
m=molality
Temperature in Kelvin
Density of water
1 g/mL
Freezing point depression
More temperature must be removed to create lattice structure
Freezing point depression equation
Delta T f=iKfm
i=van t’Hoff
Kf=proportionality constant
m=molality
Temperature in Kelvin
What is the effect of adding salt to roads?
Doesn’t change the rate of melting
Decreases the rate of freezing
Osmotic pressure
Sucking pressure genenrated by solutions in which water is drawn into the solution
Must be applied to counteract attraction of water molecules for the solution
Osmotic pressure equation
II=iMRT
i=van’t Hoff
What predicts that Rasoult’s Law will apply?
When solute-solute, solvent-solvent, solute-solvents are all very similar
Bond breaking
Endothermic
Bond making
Exothermic
Charge density
Which ions form higher charge numbers
