AI English Translation, Pages 151-175
Baghdad Province Education Directorate
Certificates and Statistics
"Confidential"
Number / 12027
Date / 2/27/55
Administrations of Official, Private, and Foreign Intermediate Schools for Boys
All ⟦line⟧
Based on the permanent expulsion of the student Muhammad Alwan from Al-Midhatiya Intermediate School,
please do not accept him upon application.
⟦signature⟧
Director of Education for Baghdad Province
Copy to: -
General Directorate of Education - referring to its letter numbered 14 / 16 / Conf. / 640
Dated 3/20/1955
Certificates and Statistics Observation
m / Amin / 24
⟦illegible⟧
Baghdad Province Education Directorate
Certificates and Statistics
Number / 215
Date / 22 / 3 / 1955
((( Secret )))
To /
Administrations of all Public, Private, and Foreign Primary, Intermediate, and Preparatory Schools
for Boys and Girls
It is not permissible to provide those dismissed as a result of inciting students to strike or those dismissed
for undesirable tendencies with documents for the purpose of their participation in external exams.
Their participation as external candidates is not permitted in any form whatsoever.
⟦signature⟧
Director of Baghdad Province Education
Copy to /
Directorate of General Cultural Affairs / with reference to its letter No. 6/11/S/45 dated
4 / 1 / 1955 for your kind information.
Assistant Mr. Abdul Sattar Al-Qara Ghuli
Personnel
Mr. Abdul Amir Al-Hammar / In charge of external statistics.
Certificates and Statistics Observer.
The Clerk
Statement for Mr. Shaoul Abu Lamda
⟦illegible⟧
20 / 4 / 1955
Sh - D / 22
⟦illegible⟧
FRANK INY SCHOOL * BAGHDAD
Directorate of Education of Baghdad Province
Certificates and Statistics
Number /:
Date /: 22 / 3 / 1955
215
((( ⟦line⟧ Secret )))
To "
Administrations of all public, private, and foreign primary, intermediate, and secondary schools
for boys and girls ⟦line⟧
It is not permissible to provide those dismissed for inciting students to strike or those dismissed
for undesirable tendencies with documents for the purpose of their participation as external candidates, and therefore
their participation as external candidates is not permitted in any form whatsoever.
⟦signature⟧
Director of Education of Baghdad Province
A copy to "
Directorate of General Cultural Affairs / Reference to its letter No. 6 / 11 / S / 45 dated
4 / 1 / 1955 for your kind information.
Assistant Mr. Abdul Sattar Al-Qarah Ghouli
Personnel ⟦line⟧
Directorate of General Cultural Affairs / Reference to our letter No. 111/6 S / 45 dated
4 / 1 / 1955 taken in the minutes.
Assistant Mr. Abdul Sattar Al-Qarah Ghouli
Personnel ⟦line⟧
Mr. Abdul Amir Al-Hammar / Acting Officer for External Candidates.
Certificates and Statistics Note ⟦line⟧
Kh - Al-D / 22
⟦illegible⟧
The Clerk
Recording the speech in the specialized notebook
⟦illegible⟧
746
3/27/1955
Directorate of Education of Baghdad Province
Number / 12710
Certificates and Statistics
Date / 3 / 24 / 1955
Administrations of all official, private, and foreign intermediate and preparatory schools for boys
We transmit to you below a copy of the letter from the Directorate of Education of Sulaymaniyah Province No. 2380 dated
3 / 14 / 1955. Please do not accept the holder upon review and consider it canceled in case they are found.
⟦signature⟧
Director of Education of Baghdad Province
Copy of the letter
The student Ali Reda Saleh claims he has lost his school document No. 606 dated
9 / 31 / 1952 issued by the administration of Sulaymaniyah Secondary School for Boys to Baqubah Evening Secondary School
So please consider it canceled and do not accept its holder upon review.
Signature / Director of Education of the Province
Sulaymaniyah
A copy to: -
Directorate of Education of Sulaymaniyah Province - referring to its letter mentioned above.
Certificates and Statistics Observation.
The Clerk
Recording the incoming in the specialized
notebook
3/24/1955
⟦illegible⟧
Baghdad
Directorate of Education of Baghdad Province
Certificates and Statistics
Number /: 12710
Date /: 24 / 3 / 1955
Administrations of all official, private, and foreign intermediate and secondary schools for boys ⟦line⟧
We transmit to you below a copy of the letter from the Directorate of Education of Sulaymaniyah Province No. 2380 dated
14 / 3 / 1955. Please do not accept its bearer upon application and consider it cancelled in case it is found
with them ⟦line⟧ .
⟦signature⟧
Director of Education of Baghdad Province
Copy of the letter ⟦line⟧
Student Ali Reda Saleh claims that he has lost his school certificate No. 606 dated
31 / 9 / 1952 issued by the administration of Sulaymaniyah Secondary School for Boys to the Evening Secondary School.
Please consider it cancelled and do not accept its bearer upon application ⟦line⟧ .
Signature / Director of Education of the Province of
Sulaymaniyah
A copy to: -
Directorate of Education of Sulaymaniyah Province - with reference to its letter mentioned above.
Certificates and Statistics Note ⟦line⟧ .
⟦illegible⟧
⟦illegible⟧ / 3 / 55
M / Amin / 23
Baghdad Liwa Education Directorate
Certificates and Statistics
No. / 12716
Date / 27 / 3 / 1955
(( Urgent ))
Subject / Dates for General and Final Examinations
To: - Administrations of all public, private, and foreign Primary, Intermediate, and Preparatory schools
for both Boys and Girls
1- It has been decided that the General Examinations for Preparatory (all branches) and Intermediate studies will begin on Saturday
corresponding to 4 / June / 1955 at eight o'clock in the morning according to the schedules shown below.
2- General Examinations for Primary studies will begin on Monday corresponding to 13 / June / 1955 at
eight o'clock in the morning according to the schedule shown below.
3- Final Examinations for non-terminal classes for all levels will begin on Saturday corresponding to
28 / May / 1955 for a period of six days.
4- School Examinations for external students for Preparatory and Intermediate studies will begin on Saturday
corresponding to 7 / May / 1955, provided they end before Monday corresponding to 16 / May / 1955.
5- School Examinations for external students for Primary studies will begin on Saturday corresponding to
14 / May / 1955 and end on Thursday corresponding to 19 / May / 1955.
Director of Education for Baghdad Liwa
A copy to: -
Head of the High Committee for Administering General Examinations / College of Engineering - Reference to their letter No. 22
dated 15 / 3 / 1955.
Assistant Mr. Abdul Sattar Al-Qarahghuli
Certificates and Statistics Observer
Personnel
Mr. Abdul Amir Al-Hammar
Notice Board / Regarding external students
⟦line⟧
To be continued
Professor Shaul Shatah
For filing
⟦illegible⟧
28 / 3 / 1955
7 / 4 / 1955
738
Supplement to the Book of Knowledge
12706
24/2/55
( 2 )
Schedule of General Examinations for Preparatory Studies - Scientific Branch - for Boys and Girls - First Session
Saturday | 4 | June | 1955 | Arabic Language
Sunday | 5 | June | 1955 | English Language
Monday | 6 | June | 1955 | Solid Geometry
Tuesday | 7 | June | 1955 | Biology
Wednesday | 8 | June | 1955 | Algebra and Trigonometry
Thursday | 9 | June | 1955 | Chemistry
Saturday | 11 | June | 1955 | Physics
Schedule of General Examinations for Preparatory Studies - Literary Branch - for Boys and Girls / First Session
Saturday | 4 | June | 1955 | Arabic Language
Sunday | 5 | June | 1955 | English Language
Monday | 6 | June | 1955 | History (Islamic and Modern)
Tuesday | 7 | June | 1955 | Geography (Physical and Economic)
Wednesday | 8 | June | 1955 | General Sciences
Thursday | 9 | June | 1955 | Economics (Childcare for Girls)
Saturday | 11 | June | 1955 | General Mathematics
Schedule of General Examinations for Preparatory Studies - Commercial Section both branches (Arabic and English) First Session
Saturday | 4 | June | 1955 | Arabic Language
Sunday | 5 | June | 1955 | English Language and English Commercial Methods
Monday | 6 | June | 1955 | Commercial Arithmetic and Financial Mathematics
Tuesday | 7 | June | 1955 | Geography
Wednesday | 8 | June | 1955 | Arabic Commercial Methods and Commercial Laws
Thursday | 9 | June | 1955 | Economics
Saturday | 11 | June | 1955 | Bookkeeping
Schedule of General Examinations for Intermediate Studies / First Session
Saturday | 4 | June | 1955 | Arabic Language
Sunday | 5 | June | 1955 | English Language
Monday | 6 | June | 1955 | Social Studies (History, Geography, and Civics)
Tuesday | 7 | June | 1955 | Natural History and Health
Wednesday | 8 | June | 1955 | Mathematics (Arithmetic, Geometry, and Algebra)
Thursday | 9 | June | 1955 | Physics and Chemistry
To be continued
Supplement to the Book of Knowledge No.
12706
4/24/55
- 3 -
⟦General Examination Schedule⟧ for Primary Studies - First Session
Monday | 13 June 1955 | Arabic Language
Tuesday | 14 June 1955 | English Language
Wednesday | 15 June 1955 | Principles of Science and Health
Thursday | 16 June 1955 | Social Studies (History and Geography)
Saturday | 18 June 1955 | Arithmetic and Measurements
Sunday | 19 June 1955 | Religion and Duties
D/22
Iraqi Ministry of Education
General Directorate of Education
Statistics
Number / ⟦illegible⟧
Date 27 / 3 / 1955
Khuraisan Region
⟦illegible⟧
Administrations of Private and Foreign Secondary Schools
We are sending you one copy (in three parts) of the statistical collection for the general population census that took place
in Iraq in the year 1947, requesting that you inform us of receipt.
General Director of Education
Dr. ⟦Muhammad⟧ Sharif
A copy to: -
The Iraqi Embassy in Washington - with thirteen copies (in three parts) of the aforementioned collection, requesting
- Cultural Attaché - their distribution to the libraries of famous universities in America and informing us of receipt
The Iraqi Embassy in London - with ten copies (in three parts) for distribution to the libraries of famous universities
- Cultural Attaché - in England. And inform us of receipt
The Iraqi Embassy in Paris - with ten copies (in three parts) for distribution to the libraries of famous universities
- Cultural Attaché - in France. And inform us of receipt
The Iraqi Embassy in Beirut - with three copies (in three parts) requesting their distribution to university libraries
- Cultural Attaché - famous in the Syrian and Lebanese regions. And inform us of receipt
The Iraqi Embassy in Ankara - with three copies (in three parts) for distribution to university libraries in Turkey
- Cultural Attaché - and inform us of receipt.
The Iraqi Embassy in Cairo - with four copies (in three parts) for distribution to university libraries in the region
- Cultural Attaché - of Egypt and inform us of receipt.
General Directorate of Census - with reference to your letter numbered 3073 dated 17 / 2 / 1955
Directorate of Statistics.
To be filed
⟦illegible⟧
4 / 4 / 1955
Al-Hadithi
⟦FRANK INY SCHOOL⟧
⟦BAGHDAD⟧
⟦Frank Iny School⟧
1955/4/20
742
Iraqi Ministry of Education
Directorate General of Education
Statistics
No. /: 1027 V.N
Date: 15 / 3 / 1955
Copy for Boys' and Girls'
Schools
Administrations of Private and Foreign Secondary Schools
We are sending you one copy (in three parts) of the statistical collection for the general population registration that took place
in Iraq in the year 947, requesting that you inform us of receipt.
Director General of Education
Dr. Mohammad Bahjat Sharif
Copy to: -
The Iraqi Embassy in Washington - with thirteen copies (in three parts) of the aforementioned collection, requesting
- Cultural Attaché - their distribution to famous university libraries in America and informing us of receipt
The Iraqi Embassy in London - with ten copies (in three parts) for distribution to famous university libraries
- Cultural Attaché - in England. And informing us of receipt
The Iraqi Embassy in Paris - with ten copies (in three parts) for distribution to famous university libraries
- Cultural Attaché - in France. And informing us of receipt
The Iraqi Embassy in Beirut - with three copies (in three parts) requesting their distribution to university libraries
- Cultural Attaché - famous in the Syrian and Lebanese regions. And informing us of receipt
The Iraqi Embassy in Ankara - with three copies (in three parts) for distribution to university libraries in Turkey
- Cultural Attaché - and informing us of receipt.
The Iraqi Embassy in Cairo - with four copies (in three parts) for distribution to university libraries in the region
- Cultural Attaché - of Egypt and informing us of receipt.
Directorate General of Civil Status - with reference to your letter No. 3073 dated 17 / 2 / 1955
Directorate of Statistics
Al-Husseini
20 / 3 / 1955
743
FRANK INY SCHOOL
Chemistry Notes for the Second Year Intermediate
1959 - 1960
I N T R O D U C T I O N
1. What is Chemistry ?
Chemistry is a science which deals with the const⟦itution⟧
of matter, its properties, its methods of preparation, its
reaction with other substances, and the changes which occur
on it.
2. What can a chemist do ?
A chemist can know the reasons for the chemical changes
of matter and can make from simple substances new preparations
which increase the prosperity of the human race. It is the
chemist who can make soap, matches, cement, photographic
films, dyes, explosives, glass and drugs. Every industry
needs the chemist and the progress of mankind lies in his
hands.
3. Is chemistry ⟦a new⟧ science?
Chemistry ⟦is still⟧ in its childhood. New discoveries
show us that there is a very wide field for investigating
the secrets of nature. There are some simple chemical re-
actions which nature can easily do, but are still not done
in the laboratory by the chemist. Our bodies are complicated
chemical factories about which we know very little.
The future will prove how little we now know about the
nature of matter and how vast is the field of science which
lies before us.
PRELIMINARY DEFINITIONS
4. Matter: Is anything that occupies a space and has a
weight e.g. iron, wood, air.
5. Body: Is a limited part of matter e.g. knife, chair.
6. Mass: Is the quantity of matter which a body contains.
7. States of matter.-
a) Solids: Are those substances that have a
definite shape and volume. Their molecules are
close to each other and have a big attraction
among them e.g. glass.
b) Liquids: Are those substances that have
variable shape and definite volume, their
molecules are somewhat close to each other and
have less attraction among them than in the
case of Solids.
Page 2
c) Gases: Are those substances which have
variable shape and volume, their molecules are
far apart from each other, and have less
attraction among them than in the case of liquids.
8. Properties of Matter
a) Physical Properties:-
Are those properties that concern the outside
appearance of the substance and have no relation
to its composition.
b) Chemical properties:-
Are those properties that concern the actual
composition and behaviour of the substance.
9. Changes of matter:-
a) Physical changes
Are temporary changes that occur on the appearance
of matter such as a change of state without any
alteration of mass e.g. 1- Melting of Wax.
2- Heating a piece of iron until it becomes red,
then white. 3- Evaporation of water.
b) Chemical changes
Are permanent changes that occur on the actual
composition of the substance with the loss of
original properties e.g.
1- The burning of wood. 2- The Rusting of iron etc.
10. Constitution of Matter
All substances are composed of very small particles
invisible to the naked eye and the microscope which
are called "molecules". These molecules are in turn
composed of smaller particles called " atoms ".
11. A Molecule:
Is the smallest part of the substance that has all
the properties of that substance.
12. An Atom:
Is the smallest part of the substance that can
enter into a chemical reaction.
/ Page 3
13. Types of Matter:-
a) An Element: Is that substance which has <del>so far</del> not been
subdivided into simpler substances. The atoms of an
element are all similar. e.g. Silver, mercury, oxygen
and hydrogen. The molecules of an element are composed
of similar atoms.
b) A Compound:-
Is that substance formed by the union of two or more
elements in definite proportions by weight so that it
differs in its properties from its constituents. The
atoms of a compound are not similar. e.g. Water is a
compound formed by the union of hydrogen and oxygen in
the ratio of 1:8 by weight.
c) A Mixture:-
Is that substance made by the addition of two or more
substances in any proportion, so that all the constit-
uents retain their original properties. e.g. Air is a
mixture of many gases.
14. Differences between Mixtures and Compounds
Compound | Mixture
1. The properties of a compound are entirely different from those of its constituents. | 1. A mixture possesses the common properties of its constituents.
2. The constituents of a compound are combined in definite proportions by weight. | 2. The proportions of the constituents of a mixture are variable.
3. The constituents of a compound cannot be separated, but by difficult chemical means. e.g. electrolysis, reduction, etc.. | 3. The constituents of a mixture can be separated easily by mechanical or physical processes e.g. by a magnet or by distillation, etc..
4. A compound is a homogeneous substance. | 4. A mixture is usually a heterogeneous substance.
Page 4
Kinds of Elements
15. There are ninety six elements in nature. They are divided into two
kinds according to their properties.
1. Metals
2. Non-Metals
Name of Metal | Symbol | Name of Metal | Symbol
Potassium | K | Nickel | Ni
Sodium | Na | Tin | Sn
Barium | Ba | Lead | Pb
Magnesium | Mg | |
Aluminium | Al | Arsenic | As
Chromium | Cr | Copper | Cu
Manganese | Mn | Mercury | Hg
Zinc | Zn | Silver | Ag
Iron | Fe | Gold | Au
Cobalt | Co | Platinium | Pt
Some important Non-Metals and their Symbols | | |
Oxygen | O₂ | Phosphorus | P
Chlorine | Cl₂ | Nitrogen | N₂
Bromine | Br₂ | Carbon | C
Iodine | I ₂ | Silicon | Si
Sulphur | S | Helium | He
| | Hydrogen | H₂
Note: 1. All symbols begin with capital letters, the second letter
is always small.
2. All gases are made up of 2 atoms except the inert gases,
they are of one atom and ozone is of three atoms.
Metals | Non-Metals
1. They are bright and reflect light when freshly cut. | 1. They are dull, and do not reflect light when freshly cut.
2. They are all solids except mercury. | 2. They are solids, liquids or gases e.g. S, Br₂, N₂
3. They are malleable & ductile. | 3. They are brittle.
4. They are good conductors of heat and electricity. | 4. They are bad conductors of heat & electricity.
5. They form basic oxides. | 5. They form acidic oxides.
6. Generally they dissolve in mineral acids and give off hydrogen. | 6. Usually they do not dissolve in mineral acids.
7. They form amalgams & alloys. | 7. They do not form amalgams & alloys.
8. Their Specific gravities are | 8. Their Specific gravities are
Page 5
19. A Solution: Is a homogeneous mixture formed by the disappearance
of the molecules of a substance called 'Solute' among the molecules
of another substance called "Solvent".
For example, the behaviour of some solids such as sugar or salt when
brought into contact with water is a familiar fact of experience,
The solid seems to disappear into the liquid, and we say that it has
"Dissolved", while the resulting homogeneous mixture is termed a
"Solution". The dissolved substance is called the "Solute" and the
liquid in which it is dissolved, the "Solvent". If we dissolve sugar
(solute) in water (solvent) the sugar will be divided into molecules.
These molecules will disappear in the spaces found among the molecules
of water and the resulting mixture is Solution of sugar in water.
20. Saturation: Is that limit beyond which apparently we cannot dissolve
any more of the solute in a certain quantity of the solvent at a
definite temperature.
21. Solubility: Is the weight (number of grams) of solute which is
sufficient to saturate 100 grams of the solvent at a certain
temperature. e.g., the solubility of sodium chloride (Na Cl) in
water at 0°C is 35.6 grams, i.e. 35.6 grams of sodium chloride will
saturate 100 gms. of water at 0 °C.
22. The general bases of Solubility:
1. The solubility of solids in liquids increases with the increase
of temperature.
2. The solubility of solids in liquids does not increase with the
increase of agitation and stirring.
3. The Mass of gases dissolved in liquids increases with the
increase of pressure.
4. The solubility of gases in liquids decreases with the increase
of temperature.
5. The boiling point (B.P.) of a liquid rises and its freezing
point becomes lower when a solid substance dissolves in it.
For examples, A solution of sugar and water boils at a
temperature higher than 100 °C and it freezes at a temperature
lower than 0 °C.
23. Kinds of Solutions:
1. A true solution: Is that solution which is homogeneous and
transparent, in which the solid particles (solute) are very
small and pass through filter paper, and do not separate
under gravity. e.g. solution of sugar in water.
2. A Colloidal solution: Is that solution which is semi-homogeneous
and semi-transparent, in which the solid particles are comparatively
large in size, do not pass easily through filter paper, and do not
settle under gravity, e.g. milk, gum, blood.
Page 6
3. A Suspension: Is that solution which is not homogeneous
and not transparent, and which consists of gross particles
of solid matter which do not pass through filter paper and
which settle under gravity, e.g. solution of chalk, or clay
in water.
24. CLASSIFICATION OF SOLUTIONS: Solutions are classified according
to the proportion of solute and solvent which they contain as
follows:-
(a) A Dilute Solution:- Is that solution which contains a small
amount of solute in proportion to the solvent.
(b) A Concentrated Solution:- Is that solution ⟦which⟧ contains a large
amount of solute in proportion to the solvent.
(c) An Unsaturated Solution:- Is that solution which contains a
quantity of solute less than that which is sufficient to
saturate it at a certain temperature and pressure. Such a
solution can dissolve more of the solute under the same
conditions of temperature and pressure. For example, if a
pinch of sugar is dissolved in a glass of water, the
solution is unsaturated because it can readily dissolve
more sugar.
(d) A Saturated Solution:- Is that solution which contains all
the solute it can normally dissolve at a given temperature
and pressure. For example, if several teaspoonfuls of sugar
are stirred in a glass of water, some of the sugar will
dissolve while the rest will drop to the bottom of the
glass. The clear solution is now said to be saturated at
the given temperature and pressure.
(e) A ⟦Supersaturated⟧ Solution:- Is that solution which contains
more of the solute than it can normally hold at the given
temperature and pressure. For example, if we dissolve 10 grams
of K Cl O₃ in 100 grams of water we get a saturated solution
at 30°C. Upon raising the temperature of this solution to
50°C, we find that the 100 grams of water will now dissolve
20 grams of K Cl O₃ then producing a saturated solution.
If the solution is carefully cooled back to 30°C, we observe
that the excess K Cl O₃ does not crystallize out, but remains
dissolved, thus yielding a solution of K Cl O₃ at 30°C which
has more solute in it than a saturated solution at that
temperature should normally have. Such a solution is said
to be "Supersaturated". This condition is unstable, for if
the solution is shaken, the 10 gms of K Cl O₃ which are in
Page 7
excess will quickly crystallize out, leaving the original
saturated solution which contains 10 gms of K Cl O₃ dissolved
in 100 grams of water at 30°C.
25. DISTILLATION:- Is the process of converting a liquid into vapour by
heat, and then condensing the vapour back to liquid again, thus
leaving behind non-volatile impurities. The pure liquid thus
gotten is called the "Distillate". A suitable apparatus for this
purpose is shown in the diagram (Fig.1).
⟦line drawing of distillation apparatus⟧
26. FILTRATION:- Is the process of running a liquid through a porous
material, such as coarse paper, sand, etc...in order to remove
suspended solid matter. The clear liquid which runs through the
filter is called "Filtrate".
⟦line drawing of filtration apparatus⟧
( Fig 2 )
27. DECOMPOSITION:- Is the process of separating a compound into its
elements or into simpler substances For example, heating
K Cl O₃ to yield K Cl and oxygen.
θ
2 K Cl O₃ ⟦line⟧→ 2 K Cl + 3 O₂
Potassium Chlorate Potassium Chloride + Oxygen
Page 8
28. Electrolysis: Is the process of decomposing a compound by means
of an electric current.
29. ANALYSIS:- Is the process of finding the composition of a substance
by decomposition into its elements or into simpler substances. For
example, water can be analysed by electrolysis yielding hydrogen
and oxygen.
Water Electric current Hydrogen + Oxygen.
Sulphuric acid ⟦line⟧
30. SYNTHESIS:- Is the combination of two or more substances, resulting
in the formation of a more complex substance. For example,
C + O₂ ⟦line⟧ C O₂
Carbon + Oxygen Carbon dioxide
31. REACTION: Any chemical change is called a reaction.
32. An Alloy: Is a substance formed by mixing together two or more
molten metals. For example, Brass is an alloy which is composed
of Copper and Zinc.
33. An AMALGAM: Is an alloy of mercury with some other metal. For
example, gold amalgam.
34. SUBLIMATION: Is the process of a solid vaporizing and then
condensing back to a solid without passing through the liquid
state. For example, sublimation of iodine.
35. PRECIPITATE: Is an insoluble substance resulting from a chemical
action between substances in solutions. For example,
Na Cl + Ag N O₃ ⟦line⟧ Ag Cl + Na N O₃
Sodium Chloride + Silver Nitrate ⟦line⟧ Silver Chloridge + Sodium
Nitrate.
x x x x x x x
36. CHEMICAL REACTIONS:
Substances often do not remain as they are, but they either
react with each other or decompose into simpler substances. Such
changes which alter the composition of a substance and form one
or more new substances, are called "Chemical Reactions". Chemistry
is a science which deals with such changes as distinguished from
other sciences.
Page 9
The Chemist has devised a highly practical system to represent
elements and compounds ⟦by⟧ means of symbols and formulas indicating
how substances are built up, and how they react with each other.
By this means he can indicate what is present in a test tube, and
what happens when something is added to it. To make this clear,
the student has to be acquainted with the following:-
(a) Symbols: A chemical symbol consists of one or two letters of
the English name or the latin name of an element denoting one
atom of it. For example, the symbol for Oxygen is O, and that
of Silver is Ag, (from Latin, Argentum).
(b) Valency or Valence: is the "Force" or "ability" of an element
to combine with other elements to form a chemical compound. This
force or ability is measured by the number of hydrogen atoms which
will combine with one atom of the element. So the valency of an
element is defined as the number of hydrogen atoms (or any
monovalent element, e.g. Chlorine) with which one atom of the
element can combine, or which it can displace. Accordingly, the
valency of an element which does not combine with any other element
is Zero, e.g. Helium. The valency of an element which combines with
one atom of hydrogen is one. Such an element is said to be "Mono-
valent"; e.g. Chlorine, in (HCl), or hydrochloric acid. The valency
of an element ⟦which combines with two atoms of hydrogen is 2. Such⟧
an element is "Divalent"; e.g. Oxygen in (H2O) or water. The valency
of an element which combines with three atoms of hydrogen is 3, and
it is "Trivalent"; e.g. nitrogen in (NH3) or ammonia and so on.
Valency could reach 8 as a maximum. Some of the elements have
constant valencies in all their compounds, while others have
variable valencies according to the kind of compound they are
prezent in, and to the condition of the reactions. The following
table gives the symbols of the important elements and their
valencies:-
Element | Symbol | Valence | Element | Symbol | Valence
Sodium | Na | 1 | Tin | Sn | 2,4
Potassium | K | 1 | Aluminium | Al | 3
Silver | Ag | 1 | Gold | Au | 3,1
Magnesium | Mg | 2 | Chlorine | Cl | 1
Calcium | Ca | 2 | Iodine | I | 1
Zinc | Zn | 2 | Oxygen | O | 2,4
Barium | Ba | 2 | Nitrogen | N | 2,3,5
Copper | Cu | 2,1 | Phosphorus | P | 3,5
Mercury | Hg | 2,1 | Carbon | C | 4,2
Iron | Fe | 2,3 | Silicon | Si | 4
Lead | Pb | 2,4 | Sulphur | S | 2,4,6
Page 21.
O X I D E S
57. DEFINITION: An oxide is a compound consisting of oxygen and one
other element.
Many compounds containing oxygen are not oxides since they consist
of three or more elements e.g. Ca CO₃.
58. CLASSIFICATION OF OXIDES:-
1- Acidic oxides: are usually non-metallic oxides. If soluble in
water they combine with it forming an acid. Their solutions in water
change blue litmus paper to red. They combine with bases to form salts
and water.
SO₃ + H₂O ⟦line⟧> H₂ SO₄
CO₂ + Ca(OH)₂ ⟦line⟧> Ca CO₃ + H₂ O
carbon dioxide calcium hydroxide calcium carbonate
acidic oxide base salt water
Examples:- Sulphur Dioxide (S O₂), Sulphur Trioxide (S O₃), Carbon
Dioxide (C O₂), phosphorus pentoxide (P₂ O₅), Sileca or Silicon
dioxide (Si O₂O, Chromium Trioxide (Cr₂ O₃).
2- Basic oxides. They are all oxides of metals. If they dissolve
in water they form an ALKALI or soluble hydroxide. Their solutions
in water change red litmus paper to blue. They combine with acids
to form salts and water.
Ca O + H₂O ⟦line⟧> Ca (OH)₂
Ca O + 2 H Cl ⟦line⟧> Ca Cl₂ + H₂ O
calcium oxide hydrochloric acid calcium chloride
Basic oxide acid salt water
Examples:- Sodium oxide (Na₂O), calcium oxide (Ca O), Copper oxide (Cu O).
3- Neutral oxides:- Are those oxides which when dissolved in water
do not affect litmus. They will combine neither with acids nor with
bases, so no salts are formed.
Examples are:- Water (H₂ O), Carbon monoxide (C O), Nitrous oxide (N₂O)
and ( N O).
Page 20
55. USES OF OXYGEN : -
(a) - uses of oxygen in the air:-
1. Respiration of both animal and plants.
2. For burning.
3. Aeration of drinking water for killing bacteria.
4. It assists certain bacteria to decay waste matter.
(b) - Uses of pure oxygen:-
1. to produce high temperature by means of oxy-hydrogen
and oxy-acetylene torches, for cutting and welding
steel. Recently, mixtures of liquid oxygen and
gasoline have been used to shoot experimental rockets
into the upper atmosphere.
2. For artificial respiration as in case of pneumonia,
drowning and (CO) poisoning.
3. For aviators and mountain climbers at high altitudes.
⟦line⟧
Page 19
2P + 5O₂ ⟦line⟧→ P₂ O₅
2 Mg + O₂ ⟦line⟧→ 2 Mg O
4 Na + O₂ ⟦line⟧→ 2 Na₂ O
4 Fe + 3O₂ ⟦line⟧→ 2 Fe₂ O₃
51. OXIDATION:- Is the union of a substance with oxygen; or the increase
in the valency of a metal; or the loss of electrons. e.g.
2 H₂ + O₂ ⟦line⟧→ 2 H₂ O
or Fe + + - e ⟦line⟧→ Fe + + +
ferrous ferric
52. COMBUSTION: Is any chemical reaction producing heat and light. It is
usually a rapid oxidation, although oxygen is not the only gas that
supports combustion. For example, sodium burns vigorously in Chlorine,
producing sodium chloride.
53. KINDLING TEMPERATURE:- Is the lowest temperature at which the substance
begins to burn. For example, yellow phosphorous has an extremely low
kindling temperature (36⁰C) and must therefore be kept under water.
On the other hand, coal has a relatively high kindling temperature.
In making fire in a stove we have to start first by igniting paper
which has a fairly low kindling temperature. The heat generated is
sufficient to raise the wood to its kindling temperature, which in
turn, heats the coal until the kindling temperature of coal is reached.
54. SPONTANEOUS COMBUSTION: - It is self-burning caused by slow oxidation
of an oxidizable substance embeded in another substance which is a bad
conductor of heat. e.g. If a piece of cotton cloth is moistened with
oil and left, the oil will gradually be oxidized and the heat generated
will not be dissipated because the cotton cloth is a bad conductor of
heat, so heat will accumulate until the kindling point of cotton is
reached and fire takes place.
Page 18.
water containing
little ⟦sulphuric⟧ acid
Oxygen
10cc
Hydrogen
20cc.
Cathode
Anode
+
Hoffman Apparatus. Fig.4
(b) Distillation of liquid air:- Air may be liquified by subjecting
it to a high pressure and a low temperature. When liquid air is
allowed to boil, the nitrogen, having a lower boiling point escapes
as a gas leaving nearly pure liquid oxygen, which is directed into
iron cylinders for transportation.
50. PROPERTIES OF OXYGEN:-
a- physical properties:-
1. It is a gas under ordinary conditions
2. It is colourless, odourless and tasteless gas.
3. It is slightly heavier than air.
4. It is sparingly soluble in water.
5. It can be liquified and solidified by subjecting it to an
extremely low temperature and a high pressure.
b- Chemical properties:-
1. Oxygen does not burn, but it supports combustion.
2. Chemically it is very active. It combines with nearly all
elements to form oxides:-
S + O₂ ⟦line⟧ SO₂
C + O₂ ⟦line⟧ CO₂
Page 17.
The manganese dioxide does not enter into the reaction. Its function
is simply to help the evolution of oxygen at a faster rate and at a
lower temperature without undergoing any change itself.
Such a substance is called "catalytic agent" or "catalyst".
A catalytic agent or (catalyst) is a subtance which changes the speed
of a chemical reaction without itself undergoing any change either in
weight or in composition.
(b)- From red mercuric oxide (Historical method). By heating red
mercuric oxide vigorously in a test tube closed by a rubber-stopper
through which passes a delivery tube, which extends to a trough
containing water, the red mercuric oxide will decompose into metallic
mercury which remains in the test tube and oxygen which passes through
the delivery tube and is collected by an upward displacement of water.
The equation for the reaction is:
2 Hg O ⟦line⟧ 2 Hg + O₂↑
Θ
2- Commercial methods:-
(a) Electrolysis of Water:- The apparatus is filled with acidified
water ( a little H₂ SO₄ is added to water to make it electrically
conductive) and a current is passed through the solution by connecting
the two platinum foils at the bottom of the two side tubes, with the
poles of an electric battery (D.C.) The platinum foils are called
"Electrodes". The water is decomposed into oxygen and hydrogen. The
oxygen collects over the positive electrode "anode", while the hydrogen
collects over the negative electrode (cathode).
The volume of hydrogen thus obtained is always twice as great as the
volume of oxygen. The Hoffman apparatus, (fig.4.), is a convenient
device for this process of electrolysis. The reaction is
2 H₂ O ⟦line⟧ 2 H₂ + O₂
H₂ SO₄
Page 16
O X Y G E N
48. OCCURRENCE. Oxygen is the most abundant element in nature. It
occurs both in the free state and combined with other elements.
1. In the free state; it is found in air in the ratio of 21 %
by volume. It is also found dissolved in water in a proportion
little more than that present in air.
2. In the combined state; it constitutes about one half of the
earth crust, eight ninths the weight of water, and about 70 %
of the living bodies.
49. METHODS OF PREPARATION
1. Laboratory methods:-
(a) From potassium chlorate. Oxygen is readily prepared in the
lab., by gently heating a mixture of potassium chlorate
(K Cl O₃) and manganese dioxide (Mn O₂). The evolved gas
is collected by an upward displacement of water as shown
in (Fig.3). The equation for the reaction is:
2 K Cl O₃ ⟦line⟧Mn O₂⟦line⟧> 2 K Cl + 3O₂↑
⟦Δ⟧
potassium potassium oxygen
chlorate chloride
K Cl O₃ + Mn O₂
Burner
delivery
Tube
oxygen
water
trough
⟦Δ⟧
2 K Cl O₃ ⟦line⟧> 2 K Cl + 3O₂↑
Fig. 3