Solutions. Types of disperse systems. True solutions. Water as most widespread solvent in pharmacy. Solvatation and heat effect of solubility process. Solubility of solid, liquids and gases (Henry law).concentration units.

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LECTURE 1
Solutions. Types of disperse systems. True
solutions. Water as most widespread solvent in
pharmacy. Solvatation and heat effect of
solubility process. Solubility of solid, liquids
and gases (Henry law).concentration units.
ass. prof. Ye. B. Dmukhalska
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PLAN

• Solubility. The mechanism of dissolving.
• Solubility of gases in liquids. The Henrys law.
• Colligative properties
• a) osmosis. The vant-Hoffs law. Hemolysis and
  plasmolysis
• b) vapor-pressure lowering of solution. A
  Raoults law
• c) boiling-point elevation
• d) freezing-point depression.

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Water main solvent

• The water - main component of organisms and
  medium, in which lives the person. The main
  properties of water that in water can solubility
  a different matters.
• In the human, animal, plant organisms the water
  is main part, a constituent solvent and it
  participates in exchange reactions of matters
  (hydrolysis, hydration, swelling, digestion).
• In a human organism are about 70 - 80 of water.
  

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The mechanism of dissolving
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• (- )Polar molecule
• (-) Negative ion
• () Positive ion
• (-)Water dipole

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• The dissolving depends primarily on the relative
  strengths of three attractive forces
• the forces between the particles of the solute
  before it has dissolved solute-solute forces),
• the forces between solvent particles before
  dissolution has taken place (solvent-solvent
  forces),
• the forces that are formed between solute and
  solvent particles during the dissolving process
  (solute-solvent forces).

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Type of solution

• A saturated solution is one that is in
  equilibrium with excess undissolved solute, or
  would be in equilibrium if excess solute were
  present. The term saturated denotes the highest
  concentration of solute which a solution can have
  and be in equilibrium with any undissolved solute
  with which it is placed in contact.
• An unsaturated solution is one in which the
  concentration of solute is less than its
  concentration in a saturated solution.
• A supersaturated solution is one in which the
  concentration of solute is greater than its
  concentration in a saturated solution.
• A supersaturated solution is unstable and its
  solute tends eventually to crystallize out of
  solution, much as a super cooled liquid tends
  eventually to crystallize.

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• Gas solution is not possible to prepare a
  heterogeneous mixture of two gases because all
  gases mix uniformly with each other in all
  proportions. Gaseous solutions have the structure
  that is typical of all gases. Air, the gaseous
  solution with which we come in closest contact,
  is composed primarily of N2 (78 by volume), O2
  (21 ), and Ar (1 ), with smaller concentrations
  of CO2, H2O, Ne, He, and dozens of other
  substances at very low levels.
• Liquid solutions have the internal structure that
  is typical of pure liquids closely spaced
  particles arranged with little order. Unlike a
  pure liquid, however, a liquid solution is
  composed of different particles. Much of this
  chapter is devoted to the properties of liquid
  solutions, and special emphasis is given to
  aqueous solutions, in which the major component
  is water.
• Two kinds of solid solutions are common. The
  first, the substitutional solid solution,
  exhibits a crystal lattice that has structural
  regularity but in which there is a random
  occupancy of the lattice points by different
  species.

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Disperse systems

• Disperse systems are called systems, which
  consist of two phases, one of which is scattered
  or dispersed in other.
• The disperse phase - phase which is scattered
  (dispersed) in medium.
• The disperse medium - phase in which dispersion
  done.

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Classification disperse systems

• By stat of dispersed phase and dispersed medium

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• By size of dispersed phase

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• Colloidal solutions are disperse systems, which
  have dispersed phase particle, which size between
  10-9 to 10-7m or 1 nm to 100 nm.

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Concentration units of solution

• Mass fraction (?i) of solute in solution is the
  ratio of the mass solute (mi) to the mass of
  solution mi ms ms- mass of a solvent
• Percentage by weight (mass) or mass percent, is
  the quantity of one component of a solution
  expressed as a percentage of the total mass
• where ?m - percent by mass,
• mA, mB, mC - mass of components in the solution.

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• Mass concentration, titer (T) is number grams of
  solute (m) per one milliliter of solution (V). Or
  it is the ratio of the quantity grams of solute
  and volume solution
• T m .
• V
• Molarity (CM), or molar concentration, is the
  number of moles of solute dissolved per liter of
  solution.
• CM ? m .
• V MV
• where CM - molarity (by mole of solute per
  liter of a solution)
• ? - number mole solute
• m - mass solute, grams
• M - molar mass solute, in grams/mole
• V - volume of the solution
• Molality is defined as the number of moles (?) of
  solute dissolved per kilogram of solvent. Thus,
  the molality of solute in a solution is
• Cm ? msolute
• msolvent M solute msolvent
• when Cm molality (by mole of solute per
  kilogram of solvent)
• ? - number of moles of solute
• m mass of solvent.

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• In measure analysis for the characteristic the
  composition of solution will use molar mass of an
  equivalent (equivalent mass)
• Molar mass of an equivalent of element is the
  mass of the element which combines with or
  displaces 1.008 parts by mass of hydrogen or 8
  part by mass of oxygen or 35.5 parts by mass of
  chlorine E fequivalence MB
• The factor of equivalence (fequiv) - number,
  which is demonstrated which part of matter
  (equivalent) can react with one atom of Hydrogen,
  or one electron in reduction reactions.
• Molar concentration of an equivalent (normal
  concentration), normality is quantity
  gram-equivalent of solute per one liter of
  solution (V)
• Ceq ?eq m .
• V E V
• where CM - molarity (by mole of solute per
  liter of a solution)
• ?eq - number mole-equivalent of solute
• m - mass solute, grams
• E - molar mass of an equivalent solute
  (equivalent mass of solute)
• V - volume of the solution

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Henry's Law

• The solubility of a gas dissolved in a liquid is
  proportional to the partial pressure of the gas
  above the liquid.
• This is a statement of Henry's law, which can be
  written
• X KP
• X is the equilibrium mole fraction of the gas in
  solution (its solubility)
• P is its partial pressure in the gas phase
• K - constant of proportionality or Henry's-law
  constant.
• The partial pressure is a part of common
  pressure, which one is a share of each gas in gas
  mixture.

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• Properties of a solution which depend only on
  the concentration of the solute and not upon its
  identity are known as colligative properties.
• vapor-pressure lowering
• boiling-point elevation
• freezing-point depression
• osmotic pressure.

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• The spontaneous mixing of the particles of the
  solute (present in the solution) and the solvent
  (present above the solution) to form ?
  homogeneous mixture is called diffusion, just as
  the term is used for the spontaneous mixing of
  gases to form homogeneous mixtures.
• A semi-permeable membrane - ? membrane which
  allows the solvent molecules to pass through but
  not the solute particles.
• The net spontaneous flow of the solvent molecules
  from the solvent to the solution or from a less
  concentrated solution to ? more concentrated
  solution through ? semi-permeable membrane is
  called osmosis (Greek push).

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• The osmotic pressure of ? solution may thus be
  defined as the equivalent of excess pressure
  which must be applied, to the solution in order
  to prevent the passage of the solvent into it
  through ? semi-permeable membrane separating the
  two, i.e. the solution and the pure solvent.
• Osmotic pressure may be defined as the
  equilibrium hydrostatic pressure of the column
  set up as ? result of osmosis.
• ? ?? ?? ? ???? or PR?C?T
• PV nRT vant Hoff equation for dilute
  solutions

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• Laws of osmotic pressure - These are the same as
  gas laws and apply to dilute solutions which
  occur in the living body

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• The effect of hypertonic and hypotonic solutions
  on animal cells.
• (?) Hypertonic solutions cause cells to shrink
  (crenation)
• (b) hypotonic solutions cause cell rupture
• (c) isotonic solutions cause no changes in cell
  volume.

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• The partial vapor pressure of a component in
  liquid solution is proportional to the mole
  fraction of that component, the constant of
  proportionality being the vapor pressure of the
  pure component.
• Raoult's law can be written as
• P1 X1 P10
• where P1 and P10 are the vapor pressure of the
  solution and that of the pure solvent,
  respectively,
• X1 is the mole fraction of the solvent in the
  solution.
• P1 is the total vapor pressure of the solution.
• X2 1 - X2,
• P1 (1- X2)P10
• P10 - P1 is the vapor-pressure lowering
• P10 - P1
• ---------- X2 fractional vapor-pressure
  lowering
• P10
• which can be seen to be equal to the mole
  fraction of the solute - X2.

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• The relationship between boiling-point elevation
  and solute concentration it can be shown that in
  dilute solutions the boiling-point elevation is
  proportional to the molality of the solute
  particles.
• if ?Tb, represents the boiling-point elevation
• ?Tboiling Tboiling (solution) - Tboiling
  (solvent),
• ?Tb KbCm
• Cm molality, number of mole of solute per one
  kilogram of solvent
• Where Cm - molality of the solute in solution
• Kb- proportionality constant known as the molal
  boiling-point elevation constant.

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• The relationship between freezing-point
  depression and molality in dilute solutions is a
  direct proportionality
• ?Tf Tfreezing(solvent) - Tfreezing(solution)
  - freezing-point depression
• ?Tfreezing KfCm
• Where Cm - molality of solute
• Kf - molal freezing-point depression constant

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Thank you for attention