Tutorial 11 Flashcards
True or False
Properties of solutions are different from that of pure solvent.
True
colligative properties
Properties that depend on the number of solute particles in solution (ions or molecules, large or small)
True or False
The effect of a solute particle of one species is considered unequal to an entirely different kind of particle.
False
The effect of a solute particle of one species is considered equal to an entirely different kind of particle.
Boiling point elevation
Increase in the boiling point when a solute is added
True or False
Solution containing 34.2 g of sucrose (mol. wt. 342) in 1000 g of water has the same osmotic pressure as a solution containing 18.0 g of anhydrous dextrose, mol. wt. 180.
True
Assumptions to apply CP equations:
- Solute is not volatile, so it does not contribute to the vapor.
- Solute does not dissolve in the solid solvent
(solvent freezes out in the pure state rather than a solid solution containing some of the solute).
True or False
solute affects the properties of the liquid phase alone and leaves the vapour and solid completely unaffected
True
Difference between diffusion and osmosis
Diffusion depends on the concentration
Osmosis depends on the osmotic pressure
Osmotic pressure
excess pressure that must be applied to the solution to prevent the passage of the solvent through a perfect semi-permeable membrane. The osmotic pressure is proportional to .the concentration of the solution
Solutions that have equal osmotic pressure
iso-osmotic or isotonic
Osmoles equation
Osmol = mol* i (number of ions)
Which is greater the osmotic pressure of electrolytes or non electrolytes solutions?
The osmotic pressure of solutions of electrolytes is considerably greater than the osmotic pressure of solutions of non-electrolytes of the same molalconcentration.
Osmotic pressure of nonelectrolytes (molarity)
piV = nRT
pi = osmotic pressure in atm.
V = the volume of solution in liters
n = the number of moles of solute
R = the gas constant equal to 0.082 liter atm/mole deg
T = the absolute temperature in kelvin
en/V = molar concentration of solute (ml/L)
This only applies where the solution is very dilute
Temp in kelvin
°C + 273
Osmotic pressure of nonelectrolytes (molality)
pi = mRT
Osmotic pressure of electrolytes
piV = inRT
i = number of ions produced by the ionization of electrolyte.
Affect of osmotic pressure on Red blood cells (erythrocytes)
Isotonic- no net osmotic pressure. Solutions to be injected into the blood should be isotonic with erythrocytes.
Hypotonic- solution has a lower concentration of electrolyte than in the body of cells (hemolysis)
Hypertonic- solution has a higher concentration of electrolyte than in the body of cells (shrinkage
Physiologic osmotic pressure
0.28 – 0.308 osmol/L = 280 - 310 mosmol/L
0.9% NaCl = 0.308 osmol/l = 308 mosmol/L
Oral Rehydration Solutions (ORS)
consists of a solution of salts and sugars
treat dehydration caused by diarrhea
lower osmolarity compared to the body (hypotonic)
decreasing the concentration of glucose and sodium chloride (NaCl).
insert a hypotonic solution to a dehydrated person so his body osmolarity is actually lower than normal, so this hypotonic solution is almost isotonic with the dehydrated body. So, by lowering the osmolarity, we are preventing the effects of hypertonicity on the net fluid absorption.
Normal osmolarity of blood/serum
300-310 mOsm/L
True or False
Hypotonic and hypertonic solutions may be infused in small volumes and into large vessels, where dilution and distribution are rapid
True
Admixtures greater than 600 to 900 mOsm/L are associated with a dramatic increase in
phlebitis
Hymolytic anemia
Very hypotonic IV solutions such as 1/4 NS cause red blood cells to swell and burst. If a sufficient number of RBC’s are so affected, the patient may develop anemia.
