Solutions Flashcards
Solutions
homogeneous mixtures of two or more substances that combine to form a single phase (usually liquid but can be any phase!)
Mixtures
gases dissolved in other gases as the moleculles do not interact chemically
Solute and Solvent
solute is dissolved into the solvent
the solvent stays in the same phase after mixing and is in greater quantity
Solvation
electrostatic interaction between solute and solvent molecules. breaking of intermolecular bonds of solute/solvents and combining solute to solvent
Also known as Dissolution and hyrdation if water is the solvent
When new interactions are stronger than original ones, the solvation is an ____ process and favored at _____ temperatures
exothermic
low
hen new interactions are weaker than original ones, the solvation is an ____ exothermic process and favored at _____ temperatures.
endothermic
high
Ideal Solution
bonds before and after solvation are equal ins strength and enthalpy is 0
Whether or not dissolution will occur spontaneously is dependent on the ______, _____ and _____ change.
gibbs free energy, enthalpy and entropy
Solubility
maximum amount of substance that can be dissolved in a particular solvent at a given temperature
Saturation
when maximum solute has been added and is in equilibrium, any more solute added will not dissolve and will precipitate
Dilute
Concentrated
when solvent:solute ratio is much larger for the solvent side
when solvent:solute ratio is much larger for the solute side
either way maximum equilibirum concentration has not been met
When change in gibbs free energy is ____, solute is soluble. When it is _____, solute is ______
soluble, insoluble
Sparingly Soluble Salts
solutes that dissolve minimally in solvent (molar solubility under 0.1 M)
Aqueous Solution
most common solution where solvent is water and interact with solute with hydration
can form hydronium ions when acids are involved
General Solubility Rules
- all salts containing ammonium and alkali metal (group 1) cations are water soluble
- all salts with nitrate (NO3-) and acetate (CH3COO-) are water soluble
- Halides except flourides are water soluble UNLESS formed with Ag+, Pb2+ and Hg2 2+
- Salts of sulfate ions are water soluble except those with Ca2+, Sr2+, Ba2_ and Pb2+
- All metal oxides are insoluble except those with alkali metals, ammonium, CaO, SrO, and BaO which form metal hydroxides
- all hydroxieds are insoluble EXCEPT those with alkali metals, ammonium, Ca2+, Sr2+ and Ba2+
- all carbonates, phosphates, sulfides and sulfites are insoluble except those with alkali metal and ammonium
General Solubility Rule you NEED to know
all salts of group 1 metals and all nitrate salts are soluble
Complex Ion Complex/Coordination Compound
molecule where cation is bonded to atleast one electron pair donor (which may include water)
help together with coordinate covalent bonds where a lewis base (electron donor) and lewis acid (electron acceptor) form bonds
found in proteins, ex: hemoglobin in blood where oxygen, CO2 and CO are ligands
Ligand
electron pair donor molecule
Chelation
central cation bonds to same ligand in multiple places
large, organic ligands
Volume Percent
volume of solute / volume solution * 100%
Units of Concentration
mass. mole fraction, molarity, molality, normality
Percent Composition by Mass
mass of solute / mass of solution *100%
Mole Fraction (X)
Xa = moles of a / tota; moles of all species
summation of mole fractions in a system = 1
Molarity (M)
moles of solute/liters of solution
Molality (m)
moles of solute/ kilograms of solvent
boiling point elevation and freezing point depression
Normality (N)
number of equivalents of interest per liter od solution
equivalent = mole of species of interest (hyroxide, proton, ion, electron)
ex: in acidic condition, 1 mole of permanganate ion accepts 5 moles electron so its normality is 5 N
Dilution
C1V1 = C2V2
C = concentration in molairty
Saturation Point
equilibrium reached during solution preparation where solute concentration is at its max at a given temp/pressure
When a solution is unsaturated/dilute, the thermodynamically favored process is _____ and the rate of dissociation will be ____ than the rate of precipitation.
As the solution becomes more concentrated and approaches saturation, the rate of dissolution _____ and the rate of precipitation _____.
At equillibrium the change in free energy is _____
dissolution
increase
decrease
decreases
increases
0
An ionic solid in a polar solvent dissociation equation
Am + Bn m A ^n+ + n B ^ m+
Solubility Product Constant (Ksp)
these are equilibrium concentrations
for formula AmBn
Ksp = [A^n+]^m * [B^m-] ^n
**dissociation reactions never have a denominator for Ksp because they always start as solids!!!
The solubility product constant_______with increases temperature for NON-GAS SOLUTES and _____ for GAS SOLUTES
Dissociation of gas solutes, Ksp will be ____ for gases at higher pressures than lower ones.
increases
decreases
higher
Ion Product (IP)
IP = [A^n+]^m * [B^m-]^n
for reaction AmBn
analogous to Q, determines where a system is with respect to equilibrium, uses ‘current’ ion concentrations
IP < Ksp -> unsaturated
IP = Ksp -> saturated
IP > Ksp -> supersaturated
Molar Solubility
molarity of a solute in a saturated solution
Why do complex ions increase the solubility of a salt in solution?
formation of multiple polar bonds leads to increased dipole interactions and stabilizes the dissociation of the ion leading to high Ksp values.
Formation/Stability Constant of Complex Ion in Solution (Kf)
formation of a complex ion after the dissolution of the original solution
the initial dissolution is the rate limiting step as it has the lower value in Ksp compared to the Kf
Solubility is impacted by:
temperature, pressure and the addition of other substances to the solution
The solubility of a salt is _______ when it is dissolved in a solution that contains one of its constituent ions compared to a pure solvent. This is known as the ________. Hence the molar solubility also ______.
However, Ksp is ______
considerably
common ion effect
decreases
constant
Colligative Properties
physical properties of solutions that are dependent on the concentration of dissolved particles but not the IDENTITY of the particles
vapor pressure depression, bp elevation, fp depression, osmotic solutions
Raoults Law
PA = XA PA(degree)
PA = vapor pressure of solvent A
XA = mole fraction of solvent
PA degree = vapor pressure of solvent A in pure state
accounts for vapor pressure depression caused by added solutes in solution
condensation rate is unaffected by the solute particles, but the evaporation rate is reduced by solute particles
applies only to ideal solutions where attraction between molecules of different components of mixture is equal to the attraction between molecules of any one component in its pure state
When a nonvolatile solute is dissolved into a solvent, the boiling point of the solution will be _____ than that of pure solvent
If vapor pressure of a solution is lower than that of a pure solvent, then ____energy (______temp) will be required before its vaporpressure = ambient pressure
greater
more , higher
deltaTb
deltaTb = iKbm
delta Tb = change in boiling point
i is vant Hoff factor number of particles produced from solute)
Kb is proportionality constant
m = molality
The presence of solute particles in a solution interferes with the formation of the ______ of solvent molecules in the solid state. Thus, a _____ amount of energy must be removed resulting in _____ temps to solidify.
lattice
greater
lesser
deltaTf
deltaTf = iKfm
Kf is proportionality for solvent
m is molality
Osmotic Pressure
pressure generated ti draw water into a solution
II - iMRT
M - molarity
R - ideal gas constant
water moves towards higher solute concentration
