HYS - CH:9 - Solubility Flashcards
solute
thing being dissolved
solvent
material doing the dissolving
units of solubility
mass per unit volume of solvent
-molarity and molality
molar solubility
- moles/Liter
solubilty product Ksp
molality
describes number of moles of solute being dissolved and what mass of solvent the solute is dissolved in
units moles of solute/kilograms of solvent
Molarity, M and preperation
how many moles of a solute are dissolved in each liter of a solvent
given the moles of solute we can find the volume
units moles/L
to prepare we
1. add solute to solution with less than target volume to not create too much of solution
2. once dissolved we add solvent until desired molarity is reached
3. measuring of volume must be done after dissolving since volume of seperate components wont add
4. divide volume by moles/volume to get molarity
why are molality and molarity nearly equivelant
1 L water ~ 1 kg water
for non aqeous solvents they can differ a lot
molAR and litER means
molarity uses liters of solvent
molAL and kilogrAM means
molality is for kg of solvent
saturated solution
as much solute dissolved as can be dissolved in that solution
molar solubility
The molar solubility is the maximum moles of dissolved solute per one liter of solvent. Notice that the unit for molar solubility is moles per liter. That’s molarity!
units moles/Liter
(same as molarity)
solubility product
special case of equilibrium constant
Ksp = [only products]
bc solids and pure liquids dont appear in equilibrium constants we have no denominator
The solubility product is a kind of equilibrium constant and its value depends on temperature. it is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution
- for when solution is saturated
- Ksp usually increases with an increase in temperature due to increased solubility.
equilibrium constant K
[products]/[reactants] with coeffficients of equation becoming exponents
. T/f? are Ksp temp and substance dependent
T
super saturated
A supersaturated solution is a solution that contains more than the maximum amount of solute that is capable of being dissolved at a given temperature
ion product: unsaturated, saturated, supersaturated
K sp equation but with current conditions
compare Ksp to IP
Ksp is a general property of solute in solvent
IP is a specific description of a solution
IP<Ksp: unsaturated less than max solute
IP = Ksp: saturated limit of solute, equilibrium
IP>Ksp: supersaturared with too much solute
if you dissolve something up to saturation in hot solvent and allow it to cool what happens to IP and KSP
Ip constant
KSP drops
useful for sugars
for what solutions does precipitation occur
supersaturated solutions
sodium barium sulfate is mixed with water to product Ba2+ and S042-. What is the Ksp?
Ksp = [Ba2+][SO4 2-]
take the product of concentration of ions
solid BaSO4 should not appear
15 grams of urea is dissolved in 100g of water. what is the molality of solution? molecular mass of urea is 60 g/mol
molality is # moles per solvent in kg
to find the moles use the mass 15 g divided by the molecular mass 60 g/mol to get 15/60 moles
we know the mass of solvent of water in kg is 100 g x 1 kg/1000 g = 0.1 kg
now take 15/60
when the concentration of table salt in water has been reached it means
the dissolved solute is in equilibrium with its undissolved state
when concentration == solubility the solution has reached saturation at its equilibrium
is CH3 COOH a salt?
has no anion and cation
not a salt
w
which alkaline earth metal has the first ionization energy
alkaline is group 2
ionization decreases top to bottom
top is Be with greater electron attraction becuase electrons are closer to nucleus in Be
electric potential energy for a point charge
moving an electron
when an electron is added to a neutral atom
energy is released, leading to a more stable state
bc neg electron is brought closer to positive nucleus which decreases energy
which is a polyatomic cation
Calcium
sulfate
hydroxide
hydronium
cation means positive
Ca2+ is a nonatomic cation
SO4 2- is a polyatomic anion
OH- is a polyatomic anion
** HsO+ is a polyatomic cation **
what kind of reaction is this
autoionization
water looses H and forms OH-
hydrogen protenates another water to form hydronium ion H30+
bronsted lowry acid and base makes
a salt plus water
which is a weak acid
HBr, HI, HF, HClO4
HF
bc products are favored than reactants, the Keq >1
when are reactants and products favored
when Keq = 1…
when keq >1…
when Keg <1…
when Keq = 1…reactants and products are favored
when keq >1…products favored
when Keg <1..reactants favored
what happens to Kw and pH
at lower temps, less heat added
reverse reaction (backwards) is favored
less H+ and less OH-
decreases Kw
as concentration H decreases, pH increases
if ph=3.7 what is pOH?
10-3.7
=10.3
which is a triprotic acid?
sulfuric acid, carbonic acid, phosphoric acid, oxalic acid
phosphoric acid has 3 dissociable hydrogen atoms … triprotic acid
