Lec1: Aqueous solutions and Colloids Dr.Ihsan Khalil
& Dr. Khawla Ahmed
Aqueous solutions and Colloids
Solutions and colloids are essential to life, the solutions in living systems are aqueous solutions; that is, they are made with water.
A solution is a homogenous mixture of two or more substances.
Types of solutions
A solution is a homogenous mixture of molecules, atoms , or ions of two, or more different substances . The substances that make up a solution are called its components .The components present in excess is called the solvent .The other are called the solutes.
The three states of matter can combine in nine different ways to form solutions containing two components.
Types of solution solvent solute example liquid liquid alcoholic beverages solid liquid gas liquid an amalgam(Hg in Ag) gas liquid solid solid salt-water solid solid metal alloys(brass or tin) gas gas air liquid gas carbonated beverages solid gas hydrogen gas in palladium
metal

Solubility
There is a limit to the amount of solute that can be dissolved in a solvent at a particular temperature. This called saturated solution. Solubility is defined as the amount of solute that dissolves in a given quantity of solvent to form saturated solution.
The solubility depends on a number of factors:
Kind of solvent, kind of solute, temperature, pressure and physical state of matter.
General Rule
Like dissolves like"
*Polar solvent ( water ) is a good solvent for ionic compounds (NaCl).
*Gasoline (non polar compounds is a good solvents for other non polar organic compounds (oil).
*A solution of liquid in a liquid, there is no limit to the amount of one substance that can dissolved in another,(Ethyl alcohol in water).Such a pair of liquids is said to be completely miscible.
*Other liquids are only slightly soluble in each other (partially miscible).
Temperature
In general,solute,are more soluble in hot than in cold solvents.
Other solids increases only slightly, and some actually decrease.See table below:-
Compounds solubility at 20 0 C solubility at 100 0
( g/100ml) (g/100ml)
NaCl 36.2 39.1
NH
4
Br 97.1 146.0
KBr 59.4 102.0

NH
3
47.5 6.9
KNO
3
37.8 247.0
O
2
0.00434 0.0008
Li
2
CO
3
1.33 0.725
CaSO
4
0.21 0.16
Gases solubilities in water decrease with increasing temperature(boiling water).
The solubility of a gas is greatly affected by the pressure of that gas above the solution.
In general ,the solubility of any gas increases as the partial pressure of the gas is increased.(solubility of O
2
&CO
2 in blood).
In contrast to gases the solubility of solids and liquids are practically unchanged with a change of pressure.
1.
Weight/Weight% Percent by weight solute 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒(𝑔)
= 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒+𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑣𝑒𝑛𝑡
x100
2. Volume/Volume percent:
Percent by volume solute 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒 𝑖𝑛 (𝑚𝑙) 𝑡𝑜𝑡𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛(𝑚𝑙) x100
3. Weight/Volume percent: 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒(𝑔)
%W/V solute= 𝑡𝑜𝑡𝑎𝑙 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛(𝑚𝑙) x100
4. Low concentrations of solute are after expressed in milligrams per
100ml.

mg/100ml= 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒(𝑚𝑔)
100𝑚𝑙 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛
(in blood& urea)
(mg percent)
5 .parts per million and part per billion (ppm &ppb) widely used to express very low concentration of solute in a solution (pollutants in water and air). 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒(𝑚𝑔)
Ppm= 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛(𝑘𝑔) kg=10 6 mg 𝑣𝑜𝑙𝑢𝑚𝑒′
=
10𝑚𝑙(1𝐿 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛)
1𝑝𝑎𝑟𝑡 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒
Ppb=
10 𝑝𝑎𝑟𝑡𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛
6. Molar concentration (M):
Is a number of moles of solute per liter of solution
𝑁𝑜.𝑜𝑓 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑒
M =
𝑁𝑜.𝑜𝑓 𝑙𝑖𝑡𝑒𝑟𝑠 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛
7.Milliequivalents per liter (meq/L)
Eq: equivalent is defined as 1mole of that ion divided by the absolute value of its charge
Ex: 1mole Na+ contains one equivalent of sodium.
1mole Mg++contains two equivalents of magnesium.
mEq/L= 𝑛𝑜.𝑜𝑓 𝑚𝑖𝑙𝑙𝑖𝑒𝑞𝑢𝑖𝑣𝑎𝑙𝑒𝑛𝑡𝑠 𝑜𝑓 𝑖𝑜𝑛 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛(𝐿)

Electrolytes and non electrolytes
An electrolyte is a substance that, when dissolved in water,results in a solution that can conduct electricity.
A nonelectrolyte does not conduct electricity when dissolved in water.
Aqueous solution that conducts electricity is called an electrolytic solution. One that does not is called a non electrolytic solution.
The mode of electrolytic and non-electrolytic solutions has been used to explain all the physical properties of solutions(osmosis and dialysis)
Osmosis and osmotic pressure:
Cells have limiting boundary membranes that are called plasma membranes. These allow the exchange of materials back and forth between the interior of the cell and it's exterior surroundings. Osmosis and dialysis are two ways that such an exchange of materials occur.
Osmosis is the movement of water though an osmotic membrane from an aqueous solution that is less concentrated to one that is more concentrated.
Preventing osmosis from occurring Appling pressure is needed to stop water movement from to place to another (osmotic pressure). The greater the number of particles, whether ions or molecules, in a solution, the greater it's osmotic pressure
Classification of solutes in Aqueous solution
Strong electrolyte
HCl weak electrolyte
CH
3
COOH nonelecrolyte
(NH
2
)
2
CO Urea
HNO3
HClO
4
HF
HNO
2
CH
3
OH
Glucose
H
2
SO
4
NH
3
Sucrose
NaOH H
2
O Nitrogen
Ba(OH)
2
Oxygen
NaCl Carbon dioxide
CaCl
2

Arrhenius Theory of Electrolytes
When ionic compounds are dissolved in water, the ions released and they distribute themselves uniformly in the water.
Polar covalent bonds form ions when dissolved in water, non electrolytes dissolve in water, neutral molecules are released.
Hydration: is a close association of water molecules with an ion and the ion said to be hydrate.
According to Arrhenius model, the total number of ions formed per mole of electrolyte depends on the chemical formula of the electrolyte. (See table below):-
KNO
CaCl
Na
3
Number of ions formed per mole of electrolyte
Chemical formula
NaCl
3
2
PO
4
Ions formed in aqueous solution
Na + Cl -
K + NO -
3
Ca + Cl Cl -
Na + Na + Na + PO
4
-3
Number of ions in 1 mole off electrolyte
2*6.02*10 23
2*6.02*10 23
3*6.02*10 23
4*6.02*10 23
2- Hypertonic: A 1M NaCl solution has a higher osmotic pressure than a
1M glucose solution, so it is hypertonic compared to 1M glucose solution.
3- Hypotonic: A 1M NaCl solution has a lower osmotic pressure than a
2M LiBr solution, so it is hypotonic compared to a 2M LiBr solution.
Osmosis occurs when a red blood cell is placed in water. The solution inside the cell is hypertonic compared to pure water, so water enters the cell. So much water enters that the cell is ruptured. The

"rupture" of red blood cells in this way is called hemolysis (cells are hemolysed).
Osmosis also occurs when a red blood cells is placed in a concentrated saline solution. In this case the solution inside the cell is hypotonic compared to the saline solution and osmosis occurs in the reverse direction. Water leaves the cell and passes in to the solution.
This causes the red blood cell to shrived and shrink. This process is called
"Crenation".
A 0.95% saline solution is isotonic compared to the solution inside the red blood cells. Consequently the cells undergo neither "Crenation" nor
"Hemlysis".
The solution to be given a patient intravenously must be isotonic with blood.
Colloids and colloidal Dispersions
The particles in a solution are the size of atoms and molecules (0.05-0.25 nm).
Sometimes intermolecular attractions between molecules cause several hundred or thousand of them to cluster together. The size of these clusters range from 1-100 nm. Matter containing particles of this size is called a "Colloid".
A uniform dispersion of a colloid in water is called a "Colloidaldispersion". A colloidal dispersion usually appears cloudy. The colloid in a colloidal dispersion is called the dispersed substance. The continuous matter in which the colloid is dispersed is called the "dispersing substance". The dispersed and dispersing substances can be liquids solids, or gases. The eight types of colloidal dispersion are listed below

Examples of Colloidal dispersion
Dispersed substance Dispersing substance
Liquid
Solid
Gas
Liquid
Solid
Gas
Gas
Liquid
Liquid
Solid
Gas
Liquid
Solid
Solid
Solid
Solid example
Fog, clouds
Smoke
Foams
Milk, butter
Paints, glue
Foam, rubber
Jellies, cheese
Colored glass, gems
Starch and proteins form colloidal dispersions in water. The particles in stable colloidal dispersions have the same electrical charge. So the particles repel each other and cannot form particles large enough to settle out.
Other colloids are stabilized in water by the action of a third substance called an "emulsifying agent".
Example: Oil and water (immiscible) if we add soap, the oil is emulsified by the soap. Soap is emulsifying agent. The soap breaks up the oil in to small drops. The soap molecules form a negatively charged layer on the surface of each oil drop. This causes the oil drops to repel each other.
Bile salts are an emulsifying agent. These salts break up the fats we eat in to small globules that can be more effectively digested.
Dialysis And Living Systems
Cell membranes that allow small molecules and ions to pass while holding back large molecules and colloidal particles are called "Dialyzing membranes". The selective passage of small molecules and ions in either direction by a dialyzing membrane is called "Dialysis". "Dialysis" differs from "Osmosis" in that osmotic membranes allow only solvent molecules to pass.

The main purpose of the kidney is to cleanse the blood by removing the waste products of metabolism and control the concentrations of electrolytes. 180L of blood are purified daily in adult (68Kg). 1 percent is eliminated as urine.
References
1Geoge H. Schmid, the chemical basis of life, Brow & Company
Boston 1982.
2Raymond Chang, chemistry, 8 th edition, Mc graw Hill, 2005.

Lec 2: Chemical Reactions in Aqueous Solutions Dr. Ihsan Khalil
& Dr.Khawla Ahmed
Salts & acids and bases form ions when dissolved in water. Many of the chemical reactions that occur in nature take place between substances dissolved in water.
Solubilities of Salts in water
Not all salts are soluble in water, but general statements can be make about the solubilities of salts:-
1All salts containing ions of elements of group IA (Li + , ……) are soluble in water no matter what the anion.
2All salts containing ammonium ions (NH
4
+ ) are soluble in water no matter what the anion.
3All salts containing nitrates ions and acetate ions are soluble in water no matter what the cation.
4All salts containing Cl - are soluble in water except when the cations are Pb 2+ , Ag + , and Hg + .
5All salts containing sulfate ions are soluble in water except when the cation are Ca 2+ , Ba 2+ , Fe 3+ , Ag + , Hg + and Pb +2 .
6All salts containing sulfide ions (S ) are insoluble in water except when the cation are Li + , Na + , K + or NH
4
+ .
7Salts containing other combination of ions are generally insoluble in water.
Ionic Reaction
Is a chemical reaction between ions or between ions and molecules. An ionic reaction occurs only if the product is one or more of the following :
1A compound insoluble in water.
2A gas.
3A compound that is soluble in water but does not exist as ions.

LiCl +NaNO
3
LiNO
3
+ NaCl
Li + + Cl Li + +NO
3
+ Na + + Cl -
NaCl + AgNO
3
AgCl +NaNO
3
Na + + Cl + Ag + + NO
3
- AgCl + Na + + NO
3
-
The net ionic equation is:
Cl + Ag + AgCl
Ions in living systems
K + & Mg +2 are found in cellular fluids. Sodium and calcium are found in the intercellular fluid.
Ca +2 ions are needed for healthy bones and teeth, blood clotting and regulation of the heart beat.
Trace elements of metallic cations are needed to maintain life hemoglobin contains iron (Fe 2+ ). These ions play an important role in the transport of O
2
and CO
2
.
Fe 2+ & Fe 3+ are part of the cytochrome system that is involved in oxidative phosphorylation.
Cu +2 , Zn +2 , Co +2 , Mn +2 assist enzymes in their biological roles.
The metallic ions present in trace amounts in living systems usually exist as "complex ions". A complex ion is made up of one or more metallic cations surrounded by other ions or molecules contain Na, O or sulfur atoms that form bonds with the metallic cation.
Complex ions are crucial to many chemical and biological processes.
Ag(NH
3
)
2
+ , Cu(CN)
4
2, Cu(NH
3
)
4
+2 , Cd(CN)
4
2-
The molecules or ions that surround the metal in a complex ion are called "ligands". Every ligand has at least one unshared pair of valence electrons

O : & N
H H H H H
The atom in a ligand that is bound directly to the metal atom is known as the "donor atom". Depending on the number of donor atoms, ligands are classified as:
Monodentate, bidentate, or polydentate.
H
2
O, NH
3
,
H N H H
2
N CH
2
CH
2
N H
2
H
Monodentate Bidentate ligand (Ethtlenediamine)
O :O: 4-
C C
: ̤ O ̈ CH
2
CH
2
: ̤ O ̈
N CH
2
CH
2
N ̈
̤ Ö CH
2
CH
2
̤ Ö
C C
: ̤ O ̈ : ̤ O :
EDTA (Polydentate ligand)
Sometimes the reaction of a metallic cation and a large molecule is poisonous to the living system (Hg 2+ , Pb +2 ). The result is that the molecules are disrupted and are prevented from performing their normal functions.

Chemical equilibrium
N
2
+ 3H
2
→ 2NH
3
(200 ˚ C + 30 atm)
2NH
3
3H
2
+ N
2
68% 32%
K=
[NH
3
[H
2
]
3
]
2
[N
2
]
equilibrium constant
3O
2
⇋ 2O
3
K=
[ O
3
]
[O
2
] 3
2

When K> 10 2 most of the reactants have been converted to products. (the products are favored).

When K< 10 -2 very small amount of product is formed. (the reactants are favored).
The LE CHATELIER principle
If the system at equilibrium is disturbed by an externally applied stress, the system changes in a way that this external stress is minimized.
Hemoglobin + 4O
2
⇋ oxyhemoglobin enzyme
Glucose - 1- phosphate ⇋ Glucose – 6 – phosphate
K=
[ glucose−6−𝑝ℎ𝑜𝑠𝑝ℎ𝑎𝑡𝑒]
[𝑔𝑙𝑢𝑐𝑜𝑠𝑒−1−𝑝ℎ𝑜𝑠𝑝ℎ𝑎𝑡𝑒]
= 20 (constant)

Ionization of water
2H
2
O ⇋ H
3
O 4 + OH -
Ionization
[H
3
O + ] = 1 * 10 -7 M
[OH ] = 1 * 10 -7 M
K=
[H
3
O
+
][ OH
−
]
[H
2
O] 3
K[H
2
O] 2 = [ H
3
O + ] [ OH ] = K `
H
2
O ⇋ H + + OH [ H
3
O + ] = [ H + ]
K = K w
= [ H + ] [OH ]
= [1*10 -7 ][1*10 -7 ] = 1*10 -14
An aqueous solution in which [H + ] is greater than [OH ] is "acidic solution". In a basic solution [OH ] is greater than [H + ].
Acids & Bases
Arrhenius defined as acid as any compound that forms a proton (H + ) in aqueous solution. A proton in solution is "Hydrated".
Strong Acid
Ionize completely when dissolved in water.
HCl + H
2
O → H
3
O + + Cl -
Strong acids Weak Acids
HCl, HBr, HClO
4
, C
2
H
3
O
2
H, H
2
CO
3
,
HI, HNO
3
, H
2
SO
4
HF, HCN

Weak acids
Ionize slightly when dissolved in water
C
2
H
3
O
2
H ⇋ C
2
H
3
O
2
+ H
3
O +
Bases
NaOH → Na + + OH -
Ca(OH)
2
& Mg(OH)
2
( strong bases)
Neutralization
1 NaOH + HCl → H
2
O + NaCl neutralization reaction
Base acid water salt solution is neither acidic nor
Basic
Na + + OH + H + + Cl - → Na + + Cl + H
2
O
Un-ionized molecule
H + + OH → H
2
O [net ionic equation]
2 H
2
SO
4
+ NaOH → NaHSO
4
+ H
2
O ………. Step 1
NaHSO
4
+ NaOH → Na
2
SO
4
+ H
2
O ………. Step 2
Overall reaction H
2
SO
4
+ 2NaOH → Na
2
SO
4
+ 2H
2
O
H + + OH → H
2
O [net ionic equation]
Reactions of acids and bases with carbonic acid and it's salts
The reaction of carbonate and carbonate salts with acids & bases are important for controlling both: aThe amount of CO
2
. bThe acidity of blood.

Lec. 3: Acids and Bases Dr. Ihsan Khalil
& Dr.Khawla Ahmed
The PH Scale
1
PH= log
[H + ]
= - log[H + ] log 10 3 = 3
[H + ] = 1*10 -PH
[OH ] = 1*10 -POH
(1*10 -PH ) (1*10 -POH ) = K w
= 1*10 -14
PH + POH = 14
[H + ] M
1*10 0 = 1
1*10 -1
1*10 -2
1*10 -14
Relationship among PH, [H + ], POH and [OH ]
PH
0
1
2
:
14
POH
14
13
12
0
[OH ]
1*10 -14 ↑ acidic
1*10 -13
1*10 0 ↓ basic
PH values of some common solution
Substance
Limit juice
Stomach acid
Soft drinks
Black coffee
Milk
Urine
Urine
0.1 M (NaOH)
PH
2.0
1-3
2-4
5
6.2-6.6
4.8-7
7-8.4
13

Measuring PH aPH meter. bBy indicator (organic compound) Litmus paper or added directly
Red at PH < 5
Blue at PH > 8.5
Acid-Base Titrations
Is a method of determining the amount of acid or base in a solution. The method is based on the chemical reaction between an acid and a base
Normality
1 mole of HCl neutralizes 1 mole of NaOH
1 mole of H
2
SO
4
neutralizes 2 moles of NaOH
1 mole of H
2
SO
4
equivalent to 2 moles of HCl.
Gram– equivalent weight of an acid = gram−molecular weight of acid number of acidic hydrogen per molecule
Gram–equivalent weight of an base = gram−molecular weight of base number of hydroxide ions per molecule

The gram - equivalent weight of a monoprotic acid is the same as its gram – molecular weight.

The gram – equivalent weight of a diprotic acid is half its gram - molecular weight.
NO. of equivalents of acid or = gram−molecular weight of acid or base gram−equivalent weight of acid or base
Base per mole of acid or base
1 mole of monoprotic acid contains 1 equivalent of acid,
1 mole of a diprotic acid contains 2 equivalents of acid. weight of sample,in (gm)
∴ Number of equivalents in a sample= gram−equivalents weight of acid or base

Normality (N)
Normality is defined as the number of equivalents of acid or base per liter of solution:
N =
Number of equivalents of acid or base
Volume of solution (L)
Normality is most useful as a unit of concentration for the calculations involved in a titration. At the equivalence point of an acid – base titration, we know that:
NO. of equivalents of base = NO. of equivalents of acid
NO.of equivalents of acid or base=normality of acid or base*volume of solution.In (L)
Normality of base + volume of base = normality of acid * volume of acid
N b
. V b
= N a
. V a
Bronsted Acids and Bases

Acid any compound or ion that donates a proton.

Base any compound or ion that accepts a proton.
Hydrogen chloride HCl/ conjugate acid- base pair
HCl + H
2
O ⇌ H
3
O + Cl -
Conjugate acid-base pair
Conjugate acid-base pair
NH
3
+ H
3
O ⇌ H
2
O + NH
4
+
Conjugate acid-base pair
H
2
O + H
2
O ⇆ H
3
O + + OH -
Acid1 base2 acid2 base1

HCO
3
+ H
3
O + ⇌ H
2
O + H
2
CO
3
"Amphoteric behavior "
Base1 acid2 base2 acid1
HCO
3
+ OH ⇌ H
2
O + CO
3
-2
Acid1 base2 acid2 base1
H
2
O + HCl ⇌ H
3
O + + Cl -
General rule
Relative strengths of some bronsted acids and their conjugate base
Acid
Chemical formula
HClO
4
HBr
HCl
Name
Perchloric acid
Hydrobromic acid
Hydrochloric
H
2
SO
H
2
O
4
HNO
3
H
3
O +
HSO
4
-
H
3
PO
4
-
C
2
H
3
O
2
H
H
2
CO
3
NH
4
+
HCO
3
-
Sulphuric
Nitric
Hydronium ion
Bisulphate
Phosphoric acid
Acetic acid
Carbonic acid
Ammonium ion
Bicarbonate ion
Water
Base
Chemical formula Name
ClO
4
Perchlorate
Br -
Cl -
HSO
4
-
NO
3
-
H
2
O
SO
4
-
H
2
PO
4
C
2
H
3
O
2
-
HCO
3
-
NH
3
CO
3
-
OH -
The stronger the acid, the weaker is its conjugate base. The weaker an acid, the stronger is its conjugate base.

Ionization constants of acids and bases
The degree of ionization of any acid is given by its ionization constant
(K a
). The equilibrium constant for the ionization of an acid in water is defined as its ionization constant.
C
2
H
3
O
2
H + H
2
O ⇌ H
3
O + + C
2
H
3
O
2
-
K=
[ H
3
[ H
2
O
+
][ C
O][ C
2
2
H
3
H
3
O
−
2
O
2
H]
]
[H
3
O + ] = [H + ]
K [H
2
O] = K a
=
[H + ][ C
2
H
3
O
−
2
[C
2
H
3
O
2
H]
]
"ionization constant"
H
2
CO
3
+ H
2
O ⇄ H
3
O + + HCO
3-
K a1
=
[ H + ][ HCO
3
[H
2
CO
3
]
]
HCO
3-
+ H
2
O ⇄ H
3
O + + CO
3
K a2
=
[ H + ][ CO
[H
2
CO
−
3
]
3
]
Acid
HCl
H
2
SO
4
HSO
4-
H
3
PO
4
H
2
PO
4
HPO
4
HF
C
2
H
3
O
2
H
H
2
CO
3
HCO
3
HCN
K a
1*10 3
1*10 2
1.2 * 10 -2
7.52 *10 -3
6.2 * 10 -8
2.2 * 10 -13
3.53 * 10 -4
1.75 * 10 -5
4.3 * 10 -7
5.61 * 10 -11
4.93 * 10 -10
PK a
3
2
1.92
2.12
7.21
12.6
3.4
4.7
6.3
10.3
9.31


Strong acids have large value of K a
.

Weak acids have small value of K a
.
PK a
= - log K a
NH
3
+ H
2
O ⇌ NH
4
+ + OH -
K =
[ NH
+
4
][ OH
−
]
[ H
2
O][ NH
3
]
K[H
2
O] = K b
=
[NH
3
][OH −
[NH
3
]
]
PK b
= - log K b
Base
PO
4-2
Zn(OH)
2
CO
3-2
Ag(OH)
NH
3
HCO
3-
Ionization constants (K b
) of some bases at 25
C
K b
4.5 * 10 -2
9.6 * 10 -4
1.84 * 10 -4
1.1 * 10 -4
1.77 * 10 -5
2.3 * 10 -8
PK b
1.34
3.02
3.74
3.96
475
7.64

Weak bases have small K b
.

Strong bases have large K b
.
Carbonic acid is weak and unstable.
H
2
CO
3
is diprotic acid,
Carbonic acid
H
2
CO
3
+ NaOH → NaHCO
3
+ H
2
O
One way reactions
NaHCO
3
+ NaOH → Na
2
CO
3
+ H
2
O
Excess base is neutralized in the body.


Carbonic acid is unstable in water. Much of the acid decomposes to CO
2
and H
2
O :
H
2
CO
3
⇌ H
2
O + CO
2
in equilibrium in water.
Equilibrium lies to the right
When CO
2
is dissolved in water, a very small amount of carbonic acid is formed.
Formulation of Carbonic acid
1When CO
2
is dissolved in water.
2Reaction of bicarbonate salt with a strong acid (HCl)
NaHCO
3
+ HCl → H
2
CO
3
+ NaCl
Unstable
We can write:
NaHCO
3
+ HCl → NaCl + H
2
O + CO
2
↑
HCO
3
+ H + → H
2
CO
3
+ CO
2
↑ net ionic equation
3Reaction of a carbonate salt with a strong acid :
Na
2
CO
3
+ HCl → NaHCO
3
+ NaCl
Na
2
CO
3
+2 HCl → 2NaCl + H
2
O + CO
2
↑
CO
3
+ 2H + → H
2
CO
3
⇌ H
2
O + CO
2
↑
Sometimes bicarbonate salts react with acids while at other times they react with bases:
OH + HCO
3
→ CO
3
+ H
2
O
H + + HCO
3
→ H
2
CO
3
+CO
2
↑
Aqueous solutions of salts aThe hydrogen and hydroxide ions are not equal in the reaction of a strong base and a weak acid.
C
2
H
3
O
2
H + NaOH ⇌ C
2
H
3
O
2
Na + H
2
O
C
2
H
3
O
2
H + OH ⇌ C
2
H
3
O
2
+ H
2
O
At equilibrium:
There are small amount of OH , Na + and unionized acetic acid in solution. As a result, the [OH ] is longer than the [H + ] and the solution is slightly basic.

Slightly basic solution can be made in two ways:
1By dissolving sodium acetate in water.
2By mixing equimolar amounts of sodium hydroxide NaOH and acetic acid.
Classification of salts
1Neutral salts: NaCl
HCl + NaOH → NaCl (neutral)
2Basic salts: C
2
H
3
O
2
Na (weak acid and strong base)
3Acidic salts: all acids whether strong or weak react
Buffer solutions
Buffer solution is a mixture of either a weak acis plus a salt of this weak acid, Or a weak base plus a salt of this base.
Such mixture react with both acids and bases, so small addition of either strong acid or strong base cause little change in the PH.
A mixture of equimolar quantities of acetic acid and sodium-acetate dissolved in water is a buffer solution.
The mixture has a large reservoir of both weak acid molecule, and the conjugate base of the acid.
Small amounts of a strong acid added to the buffer solution react with the conjugate base as:
H
3
O + + C
2
H
3
O
2
⇌ C
2
H
3
O
2
H + H
2
O {equilibrium lies to the right} weaker acid weaker base

So, the added hydrogen ion is removed from the solution and the
PH hardly changes.

OH added o the buffer solution react with molecules of acetic acid to form acetate ion and H
2
O:
OH + C
2
H
3
O
2
H ⇌ C
2
H
3
O
2
+ H
2
O {equilibrium lies to the right}

So most OH are removed from solution and the PH is only changed slightly.

∴ PH = PK a
+ log
[ C
2
[C
2
H
H
3
3
O
−
2
O
2
]
H]
{ Henderson-Hasselbalch eq.}
Addition of small amounts of a strong acid to an unbuffered solution causes drastic changes in its PH. A buffer solution has a limited ability to react with acids and bases without drastically changing its PH.

Acting as buffer because:
It contains both members of a conjugate acid-base pair. Removal of one of these two by either chemical or physical process destroys the buffer acition of the solution.

Continued addition of strong acids or bases to a buffer solution eventually exhausts its ability to act as a buffer.
Buffer solution are important in the body, because they maintain the cid-base balance in the blood.
Acid-Base balance in Blood
Buffers are very important to chemical and biological systems. The
PH in the human body varies greatly from one fluid to another:
PH of blood = 7.4
PH gastric juice = 1.5
PH values, which are crucial for proper enzyme function and the balance of osmotic pressure, are maintained by buffer in most cases.
H
2
PO
4
& HPO
4
-2
HPO
4
-2 + H
3
O + ⇌ H
2
PO
4
+ H
2
O
H
2
PO
4
+ OH → H
2
PO
4
+ H
2
O
Another buffer
CO
2
+ H
2
O ⇌ H
2
CO
3
⇌ HCO
3
+ H +
Normally in blood there is 24 m Eq/L of HCO
3
to 1.2 m Eq/L of H2CO3
PH = 7.35 – 7.45
20
1 𝑏𝑖𝑐𝑎𝑟𝑏𝑜𝑛𝑎𝑡𝑒 𝑐𝑎𝑟𝑏𝑜𝑛𝑖𝑐 𝑎𝑐𝑖𝑑

When the ratio [HCO
3
]/[H
2
CO
3
] <
20
acidic condition (PH< 7.35) This
1 called "acidemia"
The PH of the blood becomes more basic within the ration
[HCO
3
] / [H
2
CO
3
] > 20/1 (PH>7.45) "alkalemia"
PH > 6.8 PH > 7.8 ……. Death acidic basic
In the body
The body can replenish components of the buffer solution as they are used up or can remove from the body any excess component.
1Patient with an increase in the concentration of acidic product in the blood.
The physiological processes that causing acidemia are called
acidosis. The acidic product react with bicarbonate ions to produce carbonic acid. This cause [HCO
3
]/[H
2
CO
3
] "to decrease"
Lmgs & Kidneys maintain the PH by replenishing the buffer components that are used up or removing any excess components from the body.

Increase in H
2
CO
3
causes a corresponding increase in the amount of CO
2
. To lose the excess of CO
2
deeper and faster breath called
"Hyperventilation" occurs.
Kidneys can help by releasing more bicarbonate ion into the blood and removing H + ion.
2Patient has an illness that causes an increase in the concentration of basic products:
The physiological processes causing alkalimia are called alkalosis.
The basic products react with carbonic acid to form bicarbonate ion.
The ratio [HCO
3
]/[H
2
CO
3
] increases

CO
2
should be conserve and use it to produce more carbonic acid.

To do this, loss of CO
2
through the lung is minimized by slower and shallow breathing, called "hypoventilation". The kidneys can help,

by removing bicarbonate ions and hydrogen ions are added to the blood.

Lec. 4: Radioactivity and Nuclear Chemistry Dr. Ihsan Khalil
Nuclear chemistry is the study of reactions changes in atom nuclei. This brunch of chemistry began with the discovery of natural "radioactivity" by 'Antoine Becquerel' and grew as a result of subsequent investigations by Pierre and Marie Curie and many others.
The nuclei of unstable isotopes undergo spontaneous nuclear reactions that cause "Particles" and "energy", called "Nuclear radiation", to be given off. The emission of these particles and energy by isotope is called
"radioactivity". All elements having an atomic number greater than 83
(Bi) are radioactive.
Example:- Po – 210 (
84
Po 210 )
Nuclear Stability
The stability of any nucleus is determined by the difference between "Coulombic repulsion" and the "short-range" attraction. If repulsion outweighs attraction, the nucleus disintegrates, emitting particles and/or radiation.
The principle factor that determines whether a nucleus is stable is the n/p ratio. n/p ~ 1 for low atomic number n/p > 1 for high atomic number
The following rules:
1Nuclei that contain 2, 8, 20, 50, 82 or 126 protons or neutrons are generally more stable than nuclei that do not possess these numbers (Magic numbers).
2Nuclei with even number of both n & p are generally more stable than those with odd numbers of these particles.

3All isotopes of the elements with atomic numbers higher than 83 are "radioactive". All isotopes of technetium (Tc Z = 43) and promethium (Pm, Z = 61) are radioactive.
Types of radiation
1Alpha radiation (α ): is a stream of particles moving at about 1/10 the speed of light. Each particle is the nucleus of "helium atom".
That contain (2P and 2n) and has charge of +2. ( 4
2
He). they cannot travel very far without colliding with other particles. As a result, these particles do little damage to "internal organs" because they cannot penetrate the skin, but when gets inside the body by being inhaled or swallowed, the α can the damage internal organs.
212
84
Po → 208
82
Pb + 4
2
α
2Beta particles 0
-1
β :- is stream of electrons. The electrons are produced within the nucleus by the transformation of a neutron into a proton and an electron 1
0 n → 1
1
P + 0
-1
β
Example:- 40
19
K → 40
20
Ca + 0
-1
β
3Gamma radiation Ȣ :- is a form of energy similar to light waves, Xray. This radiation has high energy and can penetrate deep within the body and cause serious damage. Ȣ radiation usually occurs along with α and β radiation.

Two less common types of nuclear radiation and " 1
0 n" neutrous and "positrons" ( 0
1
β).
Type of radiation
Alpha
Composition Symbol Electric charge
α, 4
2
He +2
Approximate penetration of skin
(cm)
0.01
Beta
Gamma
Neutron
Positron
Helium nucleus
Electron
Energy
Neutron
P + ositron
β, 0
-1 e
Ȣ n, 1
0 n
B + , 0
1 e
-1
0
0
+1
1
100
10
1

Ionizing Radiation
Radiation can form ions in matter by knocking electrons off the atoms and molecules in its path. For this reason, it is called
"ionizing radiation".
They are carcinogenic, damage to the fetus and genetic damage.
Carcinogenic effect
Radiation cause cancer ( skin, bone, leukemia,…)

The effect of radiation is cumulative. High level of radiation kills cells, so precaution must be taken when dealing with radiation.

Fetuses are sensitive to radiation than adults.

Genetic risk of exposure to radiation is difficult to determine because the genetic damage may not be seen for several generation. Genetic damage is caused by damage to the gens in the nuclei of cells. The damage to the structure of the gene may cause death or variety of physical defects in following generation.

There is a risk of damage even at low levels of radiation, but the risk is extremely small.
Detection ionizing radiation
1Photographic method ( photographic imaging) I-131.
2Scintillation counter.
3Geiger-Muller counter.
4Computer imaging(Television & Computers) CAT computerized
5Film badges. Axial Tomography
Nuclear Reaction
238
92
U → 234
90
Th + 4
2
He α – decay
16
7
N → 16
8
O + 0
-1 e β – decay
99m
43
Tc → 99
43
Tc + Ȣ metastable isotop
131
53
I → 13154 Xe + 0-1 β + 0
0
Ȣ

Half – life t
1/2
The time needed for one-half of the original nuclei of an isotope to decay to another substances.
The importance of the t
1/2
is that it tells us how long a sample of the isotope will exist.
234
90
Th → 234
91
Pa + 0
-1
β t
1/2
of some Naturally occurring Radioactive isotope
Elements
Hydrogen
Carbon
Potassium
Radon
Radium
Uranium
Uranium
Polonium
Lead
Isotope
3
1
H
14
6
C
40
13
K
222
86
Rn
226
88
Ra
235
92
U
238
92
U
214
84
Po
214
82
Pb t
1/2
12.3 Yr
5700 Yr
200 million Yr
3.8 days
1600 Yr
700 million Yr
4.5 billion Yr
0.15 m sec.
26.8 min
Radiation dosages (units)
Curie and Becqueral
Ci is the level of radioactivity caused by 3.7 * 10 10 radioactive disintegrations per second. It is dependant of the size of the sample.
Picocurie (10 -12 Ci)
Microcurie (10 -6 Ci)
Millcurie (10 -3 Ci)
The SI unit of radioactivity is the becqueral (Bq)
ICi = 3.7 * 10 10 Bq
To assess biological damage caused by radiation, another units must be used that can be compared: Rad

Rad
Radiation absorbed dosage, is the dosage of radiation able to transfer
2.4 * 10 -3 calories of energy to 1 kilogram of matter.
The SI unit of absorbed dose is the gray (GY). A gray is defined as 1 J of energy absorbed per 1 Kg of tissue.
100 rad = 1 GY
The dose of 1 rad from one source is not necessarily equal to a dose of 1 rad from another.
Rem
Roentgen equivalent for man, describes the biological damage caused by the absorption of different kinds of radiation by the body.
Rem = rad * RBE REB= relative biological effectiveness
RBE of α = 10
RBE of β = 1
1 rem = 0.01 Sv (Sievent)
The rem is a more accurate and comparable measure of biological damage caused by different ionizing radiation.
LD
50
Value (lethal dose)
The dose that would be fetal for 50% of the exposed population within
30 days. Some biological effect, however, is detectable at a level as low as 25 rem.
LD
50
value is estimated for human to be 500 rem.
LD
50
for mammals is 250 – 1000 rem.
LD
50
for insects ~ 50000 rem.
Some microorganisms can tolerate more.

Each person receives about 100 mrem annually from natural background radiation.
Transmutation
Is changing one element in to another, either in nature or in the laboratory is called transmutation, by means of "bombardment reactions".
The bombardment process is often accomplished in the core of a nuclear reactor, where an abundance of small nuclear particles, particularly neutrons, are available. Alternatively, extremely high velocity charges particles (α and β) may be produced in particle accelerators, as a
"Cyclotron". Particle accelerators are extremely large and use magnetic and electric fields to 'push' and ' pull' charged particles toward their target at very high speeds.
Many isotopes that are useful in medicine are produced by particle bombardment:-
197
79
Au + 1
0 n → 198
79
Au tracer in the liver
98
42
Mo + 1
0 n → 99m
43
Tc + 0
-1 e for tracer application
Medical uses of radioactive isotopes
1To treat cancer
The radiation is directed at the cancer cell from either outside or inside the body, depending on the type of cancer.
Co – 60 is used externally.
I – 131 is used internally to treat thyroid gland cancer.
2As tracers to diagnose illnesses. The isotopes in the body can be followed or traced by means of the radiation given off.
Na – 24 is used to locate blockages in the circulatory system.
Radioactive isotopes used in humans must be chosen carefully:- aThe half life must be long enough to do its job yet short enough that the isotope will disappear from the body. bNo isotope that emit alpha particles are used.

Isotope
Cobalt – 60
Lodine – 131
Lodine –
Technetium 99 m TC – 99m
Technetium
99m
123
Chromium 51
Technetium
99m TC – 99m
Selected radioactive isotopes
Half life Emission
5.3 Yr
8 days
13.3 hr
6hr
6 hr
6.1 hr
β , Ȣ
β , Ȣ
β
Β
Use
Cancer therapy
Treatment of thyroid cancer and diagnosis of thyroid mal-function
Treatment thyroid cancer
Determination blood volume in body
Allow early detection of the extent of bone tumors and active sites of rheumatoid arthritis
Determine cardiac output
Brain, kidney, and lung scans
Nuclear medicine
The diagnosis of a host of biochemical irregularities or disease of the human body has been made routine through the use of radioactive
"tracers". Tracers are small amount of radioactive substances that are used as probs to study internal organs.
Example:- I – 127 the most abundant nonradioactive isotope.
I – 131 & I – 125 are radioactive and behave in the same way
And are used to study thyroid.
Isotopes with short half – lives are preferred for tracer studies.
Magnetic Resonance Imaging
Nuclei, like electrons, exist in different energy states (levels). Under the influence of electromagnetic radiation, transitions involving absorption of radiation can occur between the various nuclear states. Transition

occur in the microwave region of the electromagnetic radiation under the influence of a magnetic field.
Nuclear magnetic resonance (NMR) has become a useful tool for the study of molecules containing hydrogen.
In 1970s and 1980s this experimented technique was extended beyond tiny laboratory samples of pure compounds to the most complex sample
'the human body'. The result of these experiments is termed "Magnetic
Resonance Imaging".
MRI, requires no use of radioisotopes and is quick, safe, and painless.
Energy and Nuclear reactions
1Fission reaction: the nuclear reaction that causes an atom to split into several smaller parts is called fission reaction. This splitting process is accompanied by the release of large amount of energy.
A nuclear power plant uses a fissionable material (one that is capable of undergoing fission) such as U – 125, as fuel.

U – 235 is the only naturally occurring isotope that undergoes this reaction.

Two other isotopes formed by nuclear bombardment, PU – 239 and U – 233 also undergo fission reactions.
1
0 n + 235
92
U thermal
+ 143
54
Xe +3 1
0 n 103
42
M o
+ 131
50
Sn + 2 1
0 n + energy
90
83
Sr + Energy
135
53
I + 97
53
Y + 4 1
0 n + Energy

Each neutrons released react with other nuclei this is called chain reaction. The amount of material needed for a chain reaction to continue is called the "Critical Mass".
Breeder Reactors
A breeder reactor uses U – 238 which is abundant but non fissionable, in a series of steps the U – 238 is converted to PU – 239 which is fissionable and undergoes fission chain reaction, producing energy.
Nuclear fusion
Results from combination of two small nuclei to form a large nucleus with the release of large amount of energy.
2
1
H + 3
1
H → 4
2
He + 1
0 n + energy
Such fusion reaction occur in two places in the world:-
1In the sun.
2In the hydrogen bomb.
The high temperature needed to carry out the fusion reaction is furnished by the explosion of an atomic bomb. The atomic bomb is set off first and provides the uergy to trigger the hydrogen bomb.
References
1Gorge H. Schmid, the chemical basis of life, little Brow and company, 1 st edition (1982).
2Robert L. caret, Katherine J.Denniston, and Joseph J. Topping, principles and Applications of Inorganic, Organic and biological chemistry, W.m.c. Brown publisher, (1993).
3Raymond Chang, chemistry, 8 th edition, Mc Grow – Hill company publisher, (2005).

Lec.5: Pollution Dr. Ihsan Khalil
Pollution can be defined as undesirable change in our environment, as a result either, direct or indirect, action of human through an effect on type of energy, radiation level, and in chemical and physical structure of life. Pollution may affect the way of life activity such as water supply, agriculture, products, food,….
Effect of pollution
The effect of pollution may conclude human being, animals and plants, so it is important to know the sources of pollution and their effect.
Types of pollution
1Air pollution:- mainly the products of oxidation from combustion of fuels. And the air pollutant are CO, colloids, SO
2
, hydrocarbons,
No
2
(from Gasoline, diesel, natural gas, coal,…..)
Aerosols
Any suspension of colloidal or near colloidal particles in a gas is called
"Aerosol". The particles may be:
1Liquid as in mist, fog, clouds, or haze.
2Solid as fumes, dust, fly ashes or solar smoke.
3Gases as mix with the air, are dissolved in liquid droplets or adsorbed on the surface of the suspended particles.
Aerosols differ in several respects from other colloidal dispersion.
These differences are of importance in the destruction or stabilization of smoke, smog and fumes.
1In aqueous or colloidal solution, particles carry the same kind of charge. In an aerosol some of the particles may be positive some are negative and some may be uncharged.

2Aerosol particles are suspended in a low – viscosity medium and have larger "mean path", than other colloidal suspension.
3The optical and thermal properties are distinctive. The particles in some aerosols move toward light, in others the particles move away from the source of illumination. This phenomenon is called
"Photophoresis".

Soot, other solids such as iron dust, dyes, solar dust move away from the source.

Some smoke, cigarette, aerosol containing transparent, liquid droplets, sulfur and selenium aerosol move towards the incident beam.
4All aerosol are repelled by a hot object but tend to adhere to a cold surface.
5 The particles in an aerosol absorb and concentrate gases and vapors on their surface.
Smoke
Smoke is an aerosol produced by incomplete combustion. It varies in composition and properties with the fuel and oxidation condition.
Smoke from fire is different from smoke of a mechanically fired industrial plant.
Cigarette smoke is largely a suspension of liquid droplets, aqueous solutions, oil, and tars.
Soft coal and heavy oils, when burned with insufficient oxygen, produce the dirtiest and most corrosive type of smoke.

The complex aerosol know as smoke may contain toxic gases, CO,
H
2
S under poor oxidizing conditions, and So
2
, So
3
, NO, No
2
and CO
2 in normal combustion as well as unsaturated hydrocarbon vapors and droplets, aldehydes, peroxides, tars, organic acids, soot, dust, fly – ash and other solid.

The aerosol formed by the reaction of some of the components of smoke with fog or water vapor has been dubbed smog. It reduces

visibility and cuts of the UV radiation. It causes eye and throat irritation.
The primary cause of this noxious cloud was SO
2
. Today, we are more familiar with "Photochemical smog", which is formed by the reactions of automobile exhaust in the presence of sunlight.
Automobile exhaust consists mainly of No, CO, and various unburned hydrocarbons. These gases are called "Primary pollutants" because they set in motion a series of photochemical reactions that produce
"Secondary Pollutants". It is the secondary pollutants – chiefly No
2 and O
3
– that are responsible for the buildup of smog.
N
2(g)
+ O
2(g)
→ 2NO
(g)
NO when release into the atmosphere
2NO
(g)
+ O
2
→ 2NO
2(g)
oxidation
λ < 400 nm
NO
2(g)
+ hv → NO
(g)
+ O
(g) reactive
O
(g)
+ O
2(g)
+ M → O
3(g)
+ M M is the inert substance such as N
2
Ozone
Ozone can be formed also by a series of very complex reactions involving unburned hydrocarbons, nitrogen oxides, and oxygen.
There is a typical variation with time of primary and secondary pollutants.
NO + O
2
→ NO
2
{when solar radiation penetrates the atmosphere}
Ozone concentration also rise rapidly. The actual amounts depend on the location, traffic and weather conditions, but their presence is always accomplished by haze.


The oxidation of hydrocarbons produces droplets of alcohols, and carboxylic acids. The dispersion of these droplets in air cause scatter of sunlight and reduce visibility and make the air look hazy.
Major efforts have been made to reduce the buildup of primary pollutants:- oxidation
Co → CO
2
+ H
2
O
& unburned hydrocarbons reduction
NO → N
2
+ O
2
&NO
2
More efficient automobile engine and better public transportation system would help to decrease air pollution in Urban areas.
Pt
O
3(g)
+ CO
(g)
→ O
2(g)
+ CO
2(g)
Prevention and Cure of air pollution
By proper combustion methods (proportion of air and vaporized fuel must be regulated and four factors which must be controlled : temperature, time, turbulence, treatment of the issuing gases.)
Cure
1Low temperature catalytic returners are used.
2Control of fuel composition.
3Addition of smoke-reducing additives(ethyl nitrite and ethyl nitrate ).
4Use Pt catalyst to convert O
3
and CO to O
2
and CO
2
.
Indoor pollution
The common indoor pollutants and radon, carbon monoxide, and carbon dioxide, and formaldehyde.

1Radon (Rn)
Rn is a member of group 8A (noble gases), it's an intermediate product of the radioactive decay of Uranium – 238.
All isotopes of radon are radioactive, but radon – 222 is the most hazardous because it has the longest t
1/2
= 3.8 days. Radon is generated mostly from the phosphate minerals of Uranium.
226
88
Ra → 222
86
Rn + 4
2
He
Radon is found in higher concentrations with Uranium, this is not surprising, since radium is formed as a part of the stepwise decay of uranium.
Radon is radioactive but its radiation is not the major problem.
Since it is a gas and chemically inert, it is rapidly exhaled after breathing. Radon decays to Polonium:
222
86
Rn → 218
84
PO + 4
2
He
Polonium isotope is radioactive with long half-life, and is a nonvolatile heavy metal that can attach itself to bronchial or lung tissue and remain for a long time, emitting hazardous radiation.
2 Carbon dioxide and carbon monoxide
Both CO
2
& CO are products of combustion. CO
2
is formed in abundant of oxygen. CO & CO
2
is formed in a limited supply of oxygen.

Carbon dioxide is not a toxic gas, but it does have an asphyxiating effect. In air tight buildings, the concentration of CO
2
can reach as high as 2000 ppm by volume (3ppm outdoor).

Workers exposed to high [CO
2
] become fatigued more easily and have difficulty concentrating. Adequate ventilation is the solution to CO
2 pollution.

Co is a colorless and odorless gas and is highly poisonous. The toxicity of CO lies in its unusual ability to bind very strongly to hemoglobin. Both O
2
and CO bind to the Fe II ion in hemoglobin but the affinity of hemoglobin for CO is about 200 in times greater than that for O
2
. Carboxyhemoglobin cannot carry the oxygen needed for metabolic processes. CO can cause drowsiness and headache, death may result when half the hemoglobin molecules are complexed with CO. the best first aid response to CO poisoning is to remove the victim immediately to an area with a plentiful oxygen supply or to give mouth – mouth resuscitation.
3Formaldehyde (CH
2
O)
Is a disagreeable – smelling liquid used as a preservative for laboratory specimens. Formaldehyde resins are used as a bonding agent in building and furniture materials. In addition Urea – formaldehyde insulation foams are used to fill wall cavities.
Free formaldehyde is released under acid and humid conditions.
Low concentrations of formaldehyde in the air can cause drowsiness nausea, headache, breathing high concentrations of formaldehyde can induce cancers in animals, but whether it has a similar effect in humans in unclear. The safe standard of formaldehyde in indoor air has been set at 0.1 ppm by volume. oxidant such as Al
2
O
3
/KM n
O
4
,which converts formaldehyde to less volatile formic acid (HCOOH).

Water pollution
1.
Presence of organic substances degridated by microorganisms
(food),so it consume O
2
which reduce O
2
in water that cause a death of many animals living in water.
Microorganism + O
2
H
2
S (odour)
From nitrate
In water
2.
Factories and industrial plants product and houses.
3.
Presence of Hg in water lead to poisonous of fish human.some microorganism change Hg + to CH
3
Hg + soluble.
4.
Suspense particles.
5.
Radioactive isotopes from reactors which contaminate water and underground water.
Agriculture Pollution
1. Animals products reduces the O
2
in water.
2. Presence of antiseptic and fertilizer.
3. Some chemicals taken by animals and concentrate in fats more than in meat.
4. Rain water bring NO
3
and PO
4
2 to the water and soil.

Radiation pollution
Factories used H
2
O hot water growth of some weeds
As coolant as blue – green weeds
Consumption (40 0 c)
O
2
Radiation Pollution
Radioactive waste , ionizing radiation from nuclear reactors and nuclear reactions produce radiation such as α , β , γ, neutron,this may lead to many reactions that produce free radicals,electrons ,positive species.These are all active and cause to form new species either in air
,solution ,water and soil.
Volcanoes
Active volcane emits gases ,liquids,and solids.The gases include primerly
N
2
,CO
2
,HCl,HF,H
2
S and another vapors.The volcanes are the source of two-third of the sulfure in the air.
At high temperature ,the hydrogen sulfide gas given off by a volcan is oxidized by air.
2 H
2
S(g) + 3O
2
(g) ----------------→ 2SO
2
(g) +2 H
2
O(g)
Some SO
2
is reduced by more H
2
S
2H
2
S(g) + SO
2
(g) -------------------→ 3S(s) + 2 H
2
O(g)
SO
2
+ H
2
O -------------------→ acid rain

The mechanisim for the conversion of SO
2
to H
2
SO
4
is quite complex and not fully understood. The reaction is believed to be initiated by the hydroxyl radical (OH)
REFERENCES
1.
Iloyd A. Munro, Chemistry in
Engineering,PrinticeHall,Inc.,Englewood Cliffs,N.J.(1964).
2.
Robert L.Caret, Katherine J.Denniston and Joseph
J.Topping,Wm.C.Brown publishers,(1993).
3.
Raymond Chang, Chemistry, eighth edition, McGraw –
Hill.Co.Inc (2005).