Ideal and Real Solutions Flashcards
What is a real solution?
They have changes in physical properties when mized
A~A B~B A~B
What is an ideal solution?
When its components are mixed, no change in physical properties (heat, volume) when mixed. This is because of the moleculre interactions and all molecules and their interaction in the solution are considered equal.
Ideal solutions obey Raoult’s law!
What is Raolt’s Law?
Ideal Solutions
The partial vapor pressure of each volatile constituent is equal to the vapor pressure of the pure consitituent multiple by this mole fraction in the solution (Linear Relationship)
PA = P0A XA
Ptotal = PA + PB
PA: partial vapor pressure;
p0A: vapor pressure for pure A;
XA: mole fraction of A
What is equilibrium vapor pressure?
The vapor pressure is the pressure of vapor from a liquid interface.
If the vapor is mixed with other gases, the parital pressure is the vapor pressure from the liquid.
What is the escape tendency and intermolecular interations?
The vapor pressure of a liquid determined by escaping tendacy at the gas/liquid phase
What is the graph of raoults law?
What is a real solution?
A real solution is non ideal solution
It has changes in physical properties when mixed (e.g. ethanol + water – heat exchange and volume changes)
Does not obey Raoult’s law and is nonlinear.
What is the Aerosol Formulation?
Liquefied gas system for aerosol formulation
In the pressureized package with drug concentrates
Constant vapor pressure when reach liquid/vapor equilibrium at room temperature
Aerosol Formulation
When the valve is opened:
Forced the drug mixture out of the container, the pressure drops briefly
When the valve is clsoed: equilibrium re-establishes
pressure remains constant between expulsions and the amount of drug delivered is constant during a constant opening time period.
Propellants: liquified gases
Formulatin: calculate and formulate VP
What are colligative properities?
Colligative properties are the physical protperties of solutions which depend only on the number of solute particles dissolved but not depend of the identity of the solute. Therefore, the colligative properties are related to the concentrations of the solute particles in solution. The four colligative properties for the liquid solutions include
Vapor pressure lowering
Boiling point elevation
Freezing point depression
Osmotic pressure
What happens when vapor pressure lowers?
The vapor pressure lowing is when a nonvolatile solute is combined with a volatile solvent, the lower the vapor pressure above the solution is provided by the diluted solvent.
What is boiling point elevation?
Boiling point elevations is a colligative property which is related to the vapor pressure.
Review: The boiling point corresponds to the temperature at which the vapor pressure of the substance equals the ambient pressure
Comparing solution with pure water: Only giving solution more thermo energy can give the same vapor pressure.
It can also be explained by escaping tendency
What is the freezing point depression?
Freezing point depression (lowering) is the decreasing of the melting points between the pure water and a solution (always decrese compared with pure water)
It prevents iceing of roads using CaCl2 antigreeze
Blood freezing point
The freezing point depression is proportional to the molar fraction of all the solute particles X.
delta Tf is proportional to X (mole fraction)
Delta Tf = Liso m
- *Osmotic pressure:** 6.5 atm (0°C), 7.6 atm (37°C)
- *Calculated osmolarity: ** 308 mOsmol/L of water (Calculated from NaCl only)
- *Serum osmolality: ** 290-310 mOsmol/kg of water
- *Freezing point depression Tf: ** 0.52° decreasing (below 0°C)
- *Vapor pressure lowering: ** 0.12 atm at 100°C
- *Boiling point elevation Tb: ** 0.15° (above 100°C)
