Saturated A saturated solution is one that has
dissolved in it all the solute that it can normally hold at that temperature
If it has less than the max amount of solute possible, it is unsaturated
Supersaturated
Solution hold more solute than is present in their saturated solutions
Produced by creating saturated solution at high temp and allowing it to gradually cool
Electrolyte
Solutes in aqueous solutions as ions Strong Electrolyte – solute ionized completely (highly
soluble salts or very polar covalent compounds)
NaCl → Na+ + Cl-
Weak Electrolyte – incomplete ionization occurs (poorly soluble salts or weekly polar)
HgCl2 ↔ HgCl+ + Cl-
only a small part of the HgCl2 that is dissolved is present as ions
Non-electrolyte – no ionization occurs (non-polar covalent subtances)
Ionic solutes and some very highly polar molecular solutes are electrolytes
Acids and Bases
They are electrolyte solutions Strong Acid or Base is completely ionized Weak Acids or Bases are not ionized
completely
Concentration of Electrolytes
If each compound below is a strong electrolyte, what is the total concentration of solute particles for each
1) 1.5 M NaCl2) 0.50 M MgCl23) 0.25 M Ca(NO3)2
4) 2.5 M K2S5) A mixture of 10 ml of 0.20 M NaCl and
20 ml of 0.40 M Ca(NO3)2
Vapor Pressure
When solutes are added to a solvent, the solvent molecules no longer evaporate at the same rate but they still condense at the same rate
Solution end up with lower vapor pressures than pure solvent
What Is Happening?
Raoult’s Law
Vapor pressure of a solution lowers at an extent proportional to the concentration
PA = XAPA°
PA – vapor pressure of solution
XA – mole fraction of the solvent
PA° - vapor pressure of pure solvent
Example
Calculate the new vapor pressure of a solution formed by the addition of 100g of sucrose, C12H22O11 , to 1000 g of water, if the vapor pressure of the pure water is 23.8mmHg.
Ideal Solutions
Solvent and solute are alike in size, strength, and type of interactions
When solution isn’t ideal Raoult’s Law is off If interactions between the solute and solvent
molecules is weaker than ideal, the vapor pressure difference will be less than predicted by Raoult’s Law