LECTURE 1
THEME: Solution. Coligative properties of biological
liquids. Chemistry biogenic elements. Complex compound
in biological systems
associate prof. Dmukhalska Ye. B. prepared
PLAN
1. The main concepts of solutions
2. Types of solutions
3. Heat effect of a dissolution
4. Methods for expressing the concentration of a solution
5. Vapour pressure and Raoult’s law
6. Collogative properties
• A solution is a homogeneous
mixture of two or more substances
whose composition can be varied
within certain limits
The substances which is used for prepare
the solutions are called components
• The components of a binary solution are solute
and solvent.
• Solvent (water) is a component which is
present in excess, in other words a solvent is a
substance in which dissolution takes place.
Solvent doesn’t change its physical state during
reaction of dissolution.
• Solute (sodium chloride, sugar) is a component
which is present in lesser quantity. Or solute is a
substance that dissolves.
TYPES OF SOLUTION
1. Depending upon the total components
present in the solution:
a) Binary solution (two components)
b) Ternary solution (three components)
c) Quaternary solution (four components)…..etc.
2. Depending upon the ability of the dissolution
some quantity of the solute in the solvent:
A saturated solution is one that is in equilibrium
with excess undissolved solute, or would be
in equilibrium if excess solute were present.
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.
3. Depending upon the physical states of the solute and solvent, the
solution can be classified into the following nine type:
• 4. Depending upon the physical state
• Gas solution. 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.
Concentration units of a solution
The concentration of a solution may be defined as the amount of
solute present in the solution.
1. Mass percentage or volume percentage
The mass percentage of a component in a given solution is the
mass of the com ponent per 100 g of the solution.

m solute 
100%
m( solution )
V solute

V(solvent)  V solute
• 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:
m solute 
T
V (solution )
2. Molarity
It is the number of moles of the solute dissolved per litre of
the solution. It’s represented as M or CM
CM = (М) = Moles of solute / Volume of solution in litres
or
CM = (М) = Mass of component A/ Molar mass of A *Volume of
solution in litres
The unit of molarity is mol/L, 1L = 1000 ml
n
m
CM 

V MV
n solute
m solute
CM 

v solution M soluteVsolution
3. Molality
It is the number of moles of the solute dissolved per 1000 g (or 1 kg)
of the solvent. It’s denoted by m or Cm
Cm = (m) = Moles of solute/Weight of solvent in kg
or
Cm = (m) = Moles of solute * 1000/Weight of solvent in gram
The unit of Molality is m or mol/kg
n solute
m solute
Cm 

m solvent M solutem solvent
4. Normality:
It is the number of gram equivalents of the solute dissolved per litre of the
solution. It’s denoted by N or CN
(N)= CN = Number of gram equivalents of solute/Volume of solution in litres
or
(N) = CN = Number of gram equivalents of solute *1000 / Volume of solution in ml
Number of gram equivalents of solute = Mass of solute / Equivalent mass of solute
Relationship between Normality and Molarity of Solutions
Normality = Molarity * Molar mass/Equivalent mass
5. Mole fraction - is the number of moles of one
substance (na) in the solution divided by the total number
of moles of all kinds of substances in the solution.
It’s denoted by X.
Raoult’s law for solutions containing non-volatile
solutes
Vapour pressure of the solution=Vapour pressure of the
solvent in the solution
If is the vapour pressure of the solvent over a solution
containing non-volatile solute and is its mole fraction
then according to Raolt’s law,
or
At a given temperature , the vapour pressure of a
solution containing non-volatile solute is directly
proportional to the mole fraction of the solvent
Collogative properties
The dilute solutions of non-volatile solutes exhibit certain
characteristic properties which don’t depend upon the nature
of the solute but depend only on the number of particles of the
solute, on the molar concentration of the solute. These are
called colligative properties. Thus
1. Relative lowering in vapour pressure
2. Elevation in boiling point
3. Depression in freezing point
4. Osmotic pressure
This mean that if two solutions contain equal number of solute
particles of A and B then the two solutions will have same
colligative properties
The relative lowering in vapour pressure of an
ideal solution containing the non-volatile
solute is equal to the mole fraction of the solute
at a given temperature.
where A is a solvent, B is a solute
Elevation in boiling point
The boiling point of a liquid is the temperature at which its
vapour pressure becomes equal to the atmospheric pressure.
The boiling point of the solution is always higher than that
of the pure solvent. The different in the boiling points of the
solution
and pure solvent
is called the elevation in
boiling point
It has been found out experimentally that the elevation in
the boiling point of a solution is proportional to the
molality concentration of the solution
where
is called molal elevation constant or
ebullioscopicconstant
Depression in freezing point
The freezing point is the temperature a which the solid and
the liquid states of the substance have the same vapour
pressure. The freezing point of the solution is always
lower than that of the pure solvent.
where
is the molal depression constant or molal
cryoscopic constant
Determination of Molar mass
Osmotic pressure
OSMOSIS. It is the movement of water across a semipermeable membrane from an area of high water potential
(low solute concentration) to an area of low water potential
(high solute concentration). It is a physical process in
which a solvent moves, without input of energy, across a
semi-permeable membrane (permeable to the solvent, but
not the solute) separating two solutions of different
concentrations
or
Osmosis is the phenomenon of the flow of solvent through
a semi-permeable membrane from pure solvent to the
solution.
Osmosis can also take place between the solutions of
different concentrations. In such cases, the solvent
molecules move from the solution of low solute
concentration to that of higher solute concentration.
Osmotic pressure depends upon the
molar concentration of solution
Van’t Hoff observed that for dilute solutions, the
osmotic pressure is given as:
Determination of Molar Mass from
Osmotic Pressure
Conditions for getting accurate value of molar mass
1. The solute must be non-volatile.
2. The solution must be dilute, concentration of the
solute in the solution should not be more than 5 %
3. The solute should not undergo either dissociation or
association in the solution.
If two solutions have same osmotic pressure are
called isotonic solutions or isoosmotic solutions
If a solution has more osmotic pressure than some other
solutrion , it is called hypertonic
On the other hand, a solution having less osmosis pressure
than the other solution is called hypotonic
To note that a 0,9% solution of sodium chlorine (known as
saline water) is isotonic with human blood corpuscles. In
this solution, the corpuscles neither swell nor shrink.
Therefore, the medicines are mixed with saline water before
being injected into the veins.
5% NaCl solution is hypertonic solution and when red blood
cells are placed in this solution, water comes out of the cells
and they shrink
On the other hand, when red blood cells are placed in distilled
water (hypotonic solution), water flows into the cells and
they swell or burst
• The effect of hypertonic and hypotonic solutions
on animal cells.
• (а) Hypertonic solutions cause cells to shrink
(crenation) - plasmolysis;
• (b) hypotonic solutions cause cell rupture hemolysis;
• (c) isotonic solutions cause no changes in cell
volume.
A coordination complex
• Coordination compounds are the
compounds in which the central atom
(usually metallic), is linked to а number of
ions or neutral molecules by coordinate
bonds i.е. by donation of lone pairs of
electrons by these ions or neutral molecules
to the central metal atom.
• nickel tetracarbonyl, [Ni(CO)4]
Complex compounds
А) Structure
CuSO4 + 4 NH3 = [Cu (NH3)4] SO4
[Cu (NH3)4] SO4
Complex compound
• Cu2+ - central atom
•NH3 – ligand
• [Cu (NH3)4]2+ complex ion
• SO42- -anion
Aqueous solutions that contain [Ni(H2O)6]2+, [Ni(NH3)6]2+ and [Ni(en)3]2+
(from left to right). The two solutions on the right were prepared by
adding ammonia and ethylenediamine, respectively, to aqueous
nickel(II) nitrate.
Werner’s Theory
• Alfred Werner suggested in 1893
that metal ions exhibit what he
called primary and secondary
valences.
– Primary valences were the oxidation
number for the metal (+3 on the
cobalt at the right).
– Secondary valences were the
coordination number, the number of
atoms directly bonded to the metal
(6 in the complex at the right).
• The species formed by linking of а number of
ions or molecules by co-ordinate bonds to the
central metal atom (or ion) carries positive or
negative charge, it is called a complex ion
(coordination sphera). [Fe(СN)6]4-,
[Cu(NH3)4]2+, [Ag(CN)2]-
Coordination sphere.
• The central atom and the ligands which are
directly attached to it are enclosed in square
brackets and are collectively termed as the
coordination sphere.
Metal-Ligand Bond
• This bond is formed between a Lewis acid and a
Lewis base.
– The ligands (Lewis bases) have nonbonding electrons.
– The metal (Lewis acid) has empty orbitals.
• Transition metals act as Lewis acids
• Form complexes/complex ions
Fe3+(aq) + 6CN-(aq)  [Fe(CN)6]3-(aq)
Lewis acid
Lewis base
Complex
ion
Ni2+(aq) + 6NH3(aq)  [Ni(NH3)6]2+(aq)
Lewis acid
Lewis base
Complex
ion
Complex with a net charge = complex ion
Complexes have distinct properties
• Coordination compound
– Compound that contains 1 or more
complexes
– Example
• [Co(NH3)6]Cl3
• [Cu(NH3)4][PtCl4]
• [Pt(NH3)2Cl2]
• The donor atoms, molecules or anions, which
donate а pair of electrons to the metal atom and
form co-ordinate bond with it are called
ligands.
Ligands
• classified according to the number of
donor atoms
– Examples
• monodentate = 1
chelating
• bidentate = 2
agents
• tetradentate = 4
• hexadentate = 6
• polydentate = 2 or more donor atoms
Ligands
• Monodentate ligands
– Examples:
• H2O, CN-, NH3, NO2-, SCN-, OH-, X(halides), CO, O2– Example Complexes
• [Co(NH3)6]Cl3
• K3 [Fe(SCN)6]
Ligands
• Bidentate
– Examples
• oxalate ion = C2O42• ethylenediamine (en) = NH2CH2CH2NH2
• ortho-phenanthroline (o-phen)
– Example Complexes
• [Co(en)3]3+
• [Cr(C2O4)3]3• [Fe(NH3)4(o-phen)]3+
Ligands
oxalate ion
O
O
C
O
*
ethylenediamine
2-
CH2 CH2
C
H2N
*
O
*
Donor Atoms:
*
NH2
*
ortho-phenanthroline
*
*
N
CH
N
CH
C
CH
HC
C
C
HC
C
CH
CH
CH
Ligands
oxalate ion
ethylenediamine
H
C
C
M
O
M
N
Ligands
• Chelation is a process in which a
polydentate ligand bonds to a metal ion,
forming a ring. The complex produced by
this process is called a chelate, and the
polydentate ligand is referred to as a
chelating agent.
– ethylenediaminetetraacetate (EDTA) =
(O2C-CH2)2N-CH2-CH2-N(CH2-CO2)24– Example Complexes
• [Ca(EDTA)]-2
• [Co(EDTA)]-1
Ligands
* Donor Atoms
EDTA
O
*O
C
CH2
*O
C
CH2
O
*
N
*
CH2 CH2 N
O
CH2 C
O*
CH2 C
O*
O
Ligands
EDTA
O
H
C
M
N
Coordination number
• The number of ligand donor atoms that surround
a central metal ion in a complex is called the
coordination number of the metal
• Originally, a complex implied a reversible
association of molecules, atoms, or ions through
weak chemical bonds.
• [Ag(СN)2]-, [Cu(NН3)4]2+ and [Cr(Н2О)6]3+
Common Geometries of Complexes
Coordination Number
Geometry
2
Linear
Example: [Ag(NH3)2]+
Common Geometries of Complexes
Coordination Number
4
tetrahedral
Examples: [Zn(NH3)4]2+,
[FeCl4]-
Example:
[Ni(CN)4]2-
square planar
Geometry
Common Geometries of Complexes
Coordination Number
Geometry
6
Examples: [Co(CN)6]3-,
[Fe(en)3]3+
octahedral
Coordination Number
8
Dodecahedron
Cube
Geometry
Hexagonal bipyramid
Charge on the complex ion.
• The charge carried by а complex ion is the
algebraic sum of the charges carried by central
metal ion and the ligands coordinated to the
central metal ion.
• [Ag (CN)2]• [Cu (NH3)4]2+
Complex charge = sum of charges on
the metal and the ligands
[Fe(CN)6]3-
+3
6(-1)
Neutral charge of coordination
compound = sum of charges on metal,
ligands, and counterbalancing ions
[Co(NH3)6]Cl2
+
2
6(0)
neutral compound
2(-1)
Oxidation number or oxidation state.
• It is а number that represents an electric charge which
an atom or ion actually has or appears to have when
combined with other atoms,
• oxidation number of copper in [Cu(NH3)4]2+ is +2 but
coordination number is 4.
• oxidation number of Fe in [Fe(СN)6]3- is + 3 but the
coordination number is 6.
• (i) [Cu (NНЗ)4]SO4.
• (ii) Fe in [Fe (СN)6]3• (iii)К3[Fe(С2О4)3].
• (iv) [Ni(CO)4].
Neutral charge of coordination
compound = sum of charges on metal,
ligands, and counterbalancing ions
[Co(NH3)6]Cl2
+
2
6(0)
neutral compound
2(-1)
Nomenclature of Coordination
Compounds: IUPAC Rules
• The cation is named before the anion
• When naming a complex:
– Ligands are named first
• alphabetical order
– Metal atom/ion is named last
• oxidation state given in Roman numerals
follows in parentheses
– Use no spaces in complex name
Naming Coordination Compounds
Names of Some Common Metallate
Anions
Names of Some Common Ligands
•
•
•
•
[Co(NН3)6]Cl3, hexaamminecobalt (III) chloride.
K2[PtCl6], potassium hexachloroplatinate (IV).
[Co(NO2)(NH3)3], triamminetrinitrocobalt (III)
[PtCl4(NH3)2], diamminetetrachloroplatinum (IV).
Types of complexes.
• (i) А complex in which the complex ion carries а net
positive charge is called cationic complex:
[Co(NН3)]3+Cl3 [Ni(NH3)6]2+Cl2• (ii) А complex in which the complex ion carries а net
negative charge is called anionic complex:
Na[Ag(CN)2]-, K4[Fe (CN)6]4• (iii) А complex carrying no net charge is called а neutral
complex or simply а complex:
• [Ni(CO)4], [CoCl3 (NН3)3]
Main types of complex compounds
1. With one central atom
• Ammonia complex [Cu(NH3)4]SO4
• Aqua complex[Al(H2O)6]Cl3
• acidic complex K2[PtCl4]
• complex with difference ligands K[Pt(NH3)Cl3]
• cyclic (chelates)
Me
NH2 CH2
NH2 CH2
Me
O
O
C
C
O
O
HOOC H2C
CH2
N
N
Me
H2C
Polycentral compoynds
Chain
[Cr(NH3)5 – OH – (NH3)Cr]Cl3
chelaes
(CO)5Mn – Mn(Co)5
CH2
O
O
CH2
CH2
C
C
O
O
COOH
Isomerism
• Isomers
– compounds that have the same
composition but a different arrangement of
atoms
• Major Types
– structural isomers
– stereoisomers
Geometric
Isomers
Polarimetr
Thank you for attention