Department of Bioorganic and Biological Chemistry. Bioinorganic chemistry.

I COURSE

LECTURER: Professor A.D.DZHURAEV

LECTURE 1. SOLUTIONS. THE DOCTRINE ABOUT SOLUTIONS. COLLIGATIVE PROPERTIES OF SOLUTIONS

PURPOSE OF LECTURES:Familiar with the general characteristics and the important properties of solutions, know the general properties of the solutions are very important for the future doctor, as in their practical work, he often deal with solutions. This is plain drinking water and liquid dosage forms, solutions of various substances used in clinical laboratories. The human body - urine slyunnnaya fluid, blood, lymph, tissue fluid, and others - all solutions. An important role in animal organisms is osmosis. Protoplasm is an ideal semipermeable membrane through which the cell can penetrate or removed from only certain substances, but it is not permeable to other substances. Since the walls of red blood cells are not permeable to NaCl, but permeable to H2O. In practice, the physician should be aware that if the body for therapeutic purposes must enter the aqueous solutions, these solutions must have an osmotic pressure of the osmotic pressure of blood plasma, ie, should be isotonic with it. The osmotic pressure of body fluids equal to the pressure of the solution 0.86% NaCl (saline). Very important concepts plasmolysis, hemolysis, turgor, izoosmiya future doctor should know exactly from chemistry course ..TMA web site: www.tma.uz

THE LECTURE PURPOSE: • Get acquainted with the general characteristic and the most important

properties of solutions. To know the general characteristics of solutions is much important for future physician, as in its practical activity he often had run into the solution. This and usual drinking water, and fluid medicinal forms, solutions of different materials, used in clinical laboratory. In organism of the person - the urine, lachrymal liquid, blood, lymph, tissue liquid and others - all this are solutions. The Important role in animal organism plays the osmosis. The protoplasm of the cells presents itself the ideal semi-permeable membrane, through which in cell can penetrate or delete from it only determined substances, but she not permeable for the other substances. So, walls of erythrocytes is not permeable for NaCl, but permeable for Н2O. In practical activity physician must know that if in organism in therapeutic purpose necessary to enter the water solutions, these solutions must to have an osmotic pressure, equal to osmotic to pressure of the blood plasma, i.e. must be isotonic with her. Osmotic pressure of the liquids of the persons organism is a pressure 0,86% solution of NaCl (the physiological solution).

• Very important notions plasmolysis, hameolysis, turgor, izoosmiya must to know the future physician from course of the chemistry, exactly.

DEALT of questions

The object and purpose, and bioinorganic phys-colloid chemistry

Value basis and bioinorganic chemistry in medicine Phys-colloid chemistry

Solutions and general properties of solutionsSolubility and factors affecting solubilityColligative properties of solutionsProperties of strong and weak electrolytesTMA web site: www.tma.uz

DEALT of questions

The diffusion process Osmosis and osmotic pressure Calculation of the osmotic pressure of ideal solutions based on

Mendeleev-Clapeyron equation Oncotic pressure of the solution Saturated vapor pressure of the laws of Raul solutions Protolytic acid-base theory The ionic product of water, hydrogen and hydroxyl indices             TMA web site: www.tma.uz

Clausius-Clapeyron equation:

122

1 11TTRN

N

Where: N1 and N2 solubility of gases at temperatures T1 and T2? λ-, the heat on dissolution of one mole of gas in its saturated solution.? R - universal gas constant

Dependence of the solubility of gases on the pressure

Henry's law = K P

- mass concentration of gas in a saturated solutionP - gas pressureK - constant depending on the nature of the gas

Dependence of the solubility of gases in liquids from the presence of foreign material

dependence of gas solubility in the liquid from the presence of foreign substances

Sechenov’ s Law The presence of foreign substances in the solution reduces the solubility of gases in liquids:

N lg --------- = kC N0

Ostwald's dilution law

The degree of dissociation of the electrolyte increasesweak solution

if << 1 then the К = 2С

The activity coefficient of

The activity coefficient of- the ratio of activeconcentration to the total concentration:

f = a / c

where: а – activity of the solute с - concentration f - the activity coefficient

The ionic strength of the solution

The ionic strength of the solution is the value measured half the sum of the concentrations of all the works

ions in the solution to the square of theircharge.

µ = ½ ( C1Z12 + C2Z2

2 + ….. + Cn Zn2 )

µ - ionic strength С – ion concentration Z – ion charge

Example calculation of ionic strength

In 0.1 M HCl solution contains       / H + / = 0.1 g-ion / l / Cl-/ = 0.1 g-ion / l.

    The ionic strength of the solution will be: µ = ½ ( / Н+ / Z Н 2 + / СI- / Z СI 2 ) = ½ ( 0,1 * 1

+ 0,1 * 1 ) = ½ * 0,2 = 0,1

Colligative properties of solutions

• Osmotic pressure• Lowering the vapor pressure of the solvent

over a solution• Freezing point depression in comparison

with the pure solvent• Boiling point elevation compared to the

pure solvent

Раствор сахарозы

Раствор сахарозы

H2O

H2O

полупроницаемая мембрана

One-way diffusion of solvent molecules through a semipermeable membrane (membrane) of the low concentration in the direction of greater concentration is called osmosis

The phenomenon of osmosis

h

Instrument for measuring the the osmotic pressure

solution

water

Осмометр

Полупроницаемая мембрана

Osmotic pressure. Van't Hoff's law

The pressure exerted by the molecules of the solvent on the vessel wall, due to their one-sided diffusion is called the osmotic pressureVan't Hoff's law: the osmotic pressure is directly proportional to the concentration of solute in solution = CRT – for solutions of nonelectrolytes = CRT – for electrolyte solutionswhere: - osmotic pressure, C – concentration of the solution, R –universal gas constant,T – absolute temperature, -isotonic coefficient

The equation of Mendeleev - Clapeyron. PV=n R T

V – volume of the solutionn – the number of moles of solute

if n\V = C and Р = Рosm , then Рosm=СRT PV = n R T

Determination of the molar mass of nonelectrolytes:

Р osm =СRT, if С=n\V, n=m\M Р osm = n \ V*RT, here M = m R T \ Росм V

Solutions with different osmotic pressure

isotonic solution hypertonic solution hypotonic solution

Plasmolysis

A solution with a low concentration

A solution with a high

concentration of

Hemolysis

A solution with a low concentration

A solution with a high concentration of

Raul’s law

Steam pressure at which under certain temperature comes the dynamic equilibrium, characterized by equality evaporation and condensation of liquid called the pressure of saturated steam.

Raul’s lawThe relative decrease of the vapor pressure of the solvent over a solution is equal to the mole fraction of the solute, that ratio of the number of moles of solute to the total number of moles of solute and solvent

P0 - P n P0 - P n -------- = -------- or --------- = ------ P0 n + N P0 N

Where: P0-P - the vapor pressure of the pure solvent       P - vapor pressure of the solvent over a solution

         n, N - amount of substance of solute and solvent

Boiling point elevationThe difference between the boiling temperature of the solution and the solvent is called the Boiling point elevation. It is directly proportional to the molal concentration of the solute: tboiling. = E . m

Где: t boiling. –increase the boiling point

E – ebullioscopic constantm – molal concentration of the solution

Ebullioscopy

Ebullioscopy- shows increasing boiling one molality solution compared to the pure solvent.

Freezing point depressionThe difference between the crystallization temperature of the pure solvent and the solution is said to decrease the freezing point of the solution. It is directly proportional to the molal concentration of the solute: tfreezing = K . mГде: t freezing – Lowering the freezing point;

K – cryoscopic constant m - molal concentration of the solution

CryoscopyCryoscopy shows lowering the freezing point of the solution one molality compared to the pure solvent.

Cryoscopic method for the determination of the molar mass of nonelectrolyte

∆t freezing = K m if m = q*1000\ GM , Then ∆tзам =

q- mass of soluteG – weight of the solventК – cryoscopic constant

GMgК 1000*

G*замt 1000

KgM