Topic 5 + 6 Flashcards
9. The structure and dissociation of water. Acid-base theories. The pH and pOH concept, calcula- tion of the pH of strong acids or bases, and their titration curves. Acid-base indicators
What are COLLIGATIVE PROPERTIES OF SOLUTIONS?
The physical properties of a solution that depend only on the concentration of solute particles in a given quantity of solute, not on the chemical identity of the particles.
What is vapor pressure?
the pressure exerted by a vapor above a liquid when the liquid and vapor are in equilibrium with each other.
What is vapor pressure lowering?
the pressure exerted by a vapor above a liquid when the liquid and vapor are in equilibrium with each other.
Does vapor pressure depend on temperature?
Yes
What does non-volatile solute mean?
not easily vapourized solute
Compare vapor-pressure of non-volatile solution to that of pure solvent
A solution that contains a non-volatile (not easily vapourized) solute always has a lower vapour-pressure than the pure solvent
Describe equilibrium of vapor pressure of pure solvent
Vapor pressure is higher
Describe equilibrium of vapor pressure of pure solvent
Vapor pressure is higher
→ Equilibrium is established between the liquid and vapour in a pure solvent
Describe equilibrium of vapor pressure of solution containing non- volatile solute
In a solution, hydrated solute particles reduce the number of solvent particles able to leave the liquid.
→ Equilibrium is attained at a lower vapour pressure.
Formula for Raoult’s law
vapour-pressure lowering is proportional to the mole fraction of the non-volatile solute
This is the phase diagram of which substance?
Pure water
What is boiling?
a form of evaporation where conversion from the liquid state → the vapor state occurs within the body of the liquid through bubble formation
What is boiling point?
the temperature at which the vapor pressure of a liquid becomes equal to the external (atmospheric) pressure exerted on the liquid
What is BOILING-POINT ELEVATIONt?
Addition of a nonvolatile solute to a solvent
→ makes the boiling point of the solution HIGHER than that of the solvent alone.
Calculate
Boiling-point elevation of solutions
What is FREEZING-POINT DEPRESSION?
Addition of a nonvolatile solute to a solvent
→ makes the freezing point of the solution LOWER than that of the solvent alone.
Calculate
Freezing-point depression of solutions
What is the van’t Hoff factor (i)?
The factor that denotes the total number of dissolved particles
What is the relationship between colligative properties and osmolarity of solution?
Colligative properties are proportional to the osmolarity of the solution
What is osmosis?
the passage of a solvent through a semipermeable membrane separating a dilute solution (or pure solvent) from a more concentrated solution.
What is osmosis?
the passage of a solvent through a semipermeable membrane separating a dilute solution (or pure solvent) from a more concentrated solution.
What is a semi-permeable membrane?
A membrane that allows certain types of molecules to pass through it but prohibits the passage of other types of molecules
What is a semi-permeable membrane?
A membrane that allows certain types of molecules to pass through it but prohibits the passage of other types of molecules
What is Osmotic pressure?
the pressure that must be applied to prevent the net flow of solvent through a semipermeable membrane from a solution of lower solute concentration to a solution of higher solute concentration
What is osmolarity?
The product of a solution’s molarity and the number of particles produced per formula unit if the solute dissociates.
Osmolarity = molarity x i
i - the number of particles produced from the dissociation of one formula unit of produced per formula unit if the solute dissociate
=> The abbreviation for osmolarity is osmol.
What is the osmolarity of 2M NaCl?
Osmolarity = molarity x i
2 particles per dissociation are produced when NaCl dissociates in solution.
NaCl → Na+ + Cl-
=> i is 2 → the osmolarity is twice the molarity.
Osmolarity = 2 M x 2 = 4 osmol
What is the osmolarity of 2M CaCl2?
Osmolarity = molarity x i
For CaCl2, the value of i is 3, because three ions are produced from the dissociation of one CaCl2 formula unit.
CaCl2 → Ca2+ + 2Cl-
The osmolarity will therefore be triple the molarity:
Osmolarity = 2M x 3 = 6 osmol
What is the osmolarity of 2 M glucose?
Glucose is a nondissociating solute.
→ Thus the value of i is 1, and the molarity and osmolarity will be the same—two molar and two osmolar.
What is the osmolarity of 2 M in both NaCl and glucose?
With two solutes present, we must consider the collective effects of both solutes. For NaCl, i 2; and for glucose, i 1. The osmolarity is calculated as follow
Osmolarity = 2 M x 2 = 2 M x 1 = 6 osmol
What is the formula for Osmotic pressure (π)?
- *1 mol/liter = 1 mol/0.001 m3 = 1000 mol/m3,**
- *so if concentration is given in mol/liter, you get the**
pressure in kilopascal!!!
What is HYPOTONIC SOLUTION?
- Solution with an osmotic pressure LOWER than that in cells.
- Causes cells to hemolyze (burst).
What is HYPOTONIC SOLUTION?
- Solution with an osmotic pressure HIGHER than that in cells.
- Causes cells to crenate (shrink).
What is HYPOTONIC SOLUTION?
- Solution with an osmotic pressure EQUAL to that in cells.
- Has no effect on cell size.
