Chapter 11 Flashcards
solute
Component of the solution in lesser abundance
solvent
Component of the solution in greater abundance
Homogeneous
same composition throughout
Two factors drive a spontaneous process
- A lowering of the energy of the system
➢ the particles are in a more energetically favorable
arrangement - An increased dispersal of matter in the system
➢ an increase in the entropy (randomness) of the system
Ideal solution
when structurally very similar liquids are mixed
When the strength of the IMFs between solute &
solvent are the same as in the pure substances,
there is no energy change upon dissolution
strong electrolytes
completely dissociate into ions
Weak electrolytes
dissolve mostly as molecules but partially as ions
Nonelectrolyte
A compound that does not break up into ions when dissolved in water is s a poor conductor of electricity.
ion-dipole attractions or
ion-dipole forces
Water and other polar molecules are attracted to ions
via electrostatic forces, called ion-dipole attractions or
ion-dipole forces
✓Negative end of dipole attracted to cations, positive end of
dipole attracted to anions
✓Stronger dipole moment →stronger ion-dipole force
✓Higher charge & smaller size of ion →stronger ion-dipole force
Salute-Salute interactions
ionic bonds (strong)
Does not occur in gasses
Solvent-solvent interactions
H-bonds
Salute-solvent interactions
on-dipole forces (can be strong)
supersaturated solution
A solution with more solute than the solubility limit
How does the temperature of water effect the solubility of gas?
For all gases, the solubility in water
decreases as temperature increases
✓ More disorder in gas phase than in
solution
✓ Higher temp drives molecules to be
more dispersed
Henry’s Law
Higher partial pressure of gas →more gas dissolves in
the solvent
T he solubility of a gas is directly
proportional to its partial pressure above the soln.
Cgas = kPgas
Miscible
Some liquids are soluble in each other in all
proportions
Same polarity is needed and they need the same types of bonds
Liquids that dissolve in each other
to a limited extent are partially
miscible
Immiscible
Two liquids that do not dissolve in
each other to any appreciable
extent are
Solubility of Solids in Liquids
The solubilities of solids in water varies widely
Memorize solubility rules
Remember LIKE DISSOLVES LIKE
For most ionic compound, solubility
increases w/ increasing temperature
Molecular compounds w/ lots of OH
groups tend to be soluble in water
Molecular compounds w/ only disp.
forces are not soluble in water
What does The solubility of a gas in a liquid solvent depend on?
l. Pressure
II. Temperature
III. Identity of gas
A supersaturated solution can be made to precipitate out by?
A supersaturated solution is unstable. Adding more solute will provide the seed crystals for the extra solute to crystallize from the solution. Simply agitating the solution an also start the crystallization process, producing the seed crystals for more solute to crystallize from the solution
Mass %
=mass of solute/total mass
Mole fraction
=mol of solute/total moles
Molarity
moles of solute/L of solution
Colligative properties:
properties of a solution whose value depends only on the number of solute particles (concentration),
and not on what they are
✓for ionic solutes, depend on the
total number of ions
Vapor Pressure Depression
Boiling Point Elevation
Freezing Point Depression
Osmotic Pressure
Tro, Chemistry: A Molecular Approach
Van’t Hoff Factor (i)
The concentration of solution particles is the total concentration of all ions
i= moles solution moles form
Vapor Pressure of Solutions
Vapor pressure of a solvent above a solution
is lower than the vapor pressure of the pure
solvent
Raoult’s Law
Partial Pressure= (mole fraction o solvent)(Normal pressure)
The vapor pressure should decrease!
Total vapor pressure
Is the total vapor pressure of the solute and the solvent combined
Ptot = Pa + Pb = XaP°a+ XbP°b
eqn
✓strength of A-B interactions similar to A-A and B-B interactions
Distillation
Volatile liquids with different vapor pressures can thus be separated by vaporization called distilation
CHECK OUT SLIDE 36 will be on test
Osmosis
low of solvent through a semi-permeable membrane from solution of low concentration to solution of high concentration
