Iron oxide color

Iron oxides are a type of chemical compounds composed of iron and oxygen. In total, sixteen known iron oxides and oxyhydroxides are present. There lies a great variety of usage for these various oxides and hydroxides ranging from pigments in ceramic glaze, to use in thermite.

Hematite is a key ore of iron and its blood red color (in the powdered form) provides itself well to use as a pigment. The name Hematite is derived from a Greek word meaning blood-like because of the color of its powder. There exists ancient superstition which tells that big deposits of hematite were formed from battle fought in ancient times by the blood that flowed into the ground. Crystals of Hematite are thought to be rare and are desired by collectors as are fine Kidney Ore specimens.

Properties of iron oxide

The color ranges from steel or silver gray to black in some forms and red to brown in earthy forms. Occasionally it is tarnished with gleaming colors when in a hydrated form (called Turgite).The luster is metallic or dull in earthy and oolitic forms. Transparency: Crystals are opaque. Crystal System is trigonal; bar 3 2/m Crystal Habits include tabular crystals of varying thickness sometimes twinned, micaceous (specular), botryoidal and massive. also earthy or oolitic. Cleavage is absent.

However, there is a parting on two planes.

Fracture is uneven. Hardness is 5 – 6. Specific Gravity is 5.3 (slightly above average for metallic minerals). Streak is blood red to brownish red for earthy forms. Associated Minerals include jasper (a variety of quartz) in banded iron formations (BIF or Tiger Iron), dipyramidal quartz, rutile, and pyrite among others.

Forms of iron oxide

Iron Oxide is present in many different forms which are mentioned below:

a. Alpha phase- In the Alpha phase, most common form is Rhombohedric, and occurs as the mineral hematite.

b. Beta Phase- The Beta phase is cubic face centered or metastable.

c. Gamma Phase- The Gamma phase is cubic, metastable.

d. Epsilon phase- The Epsilon phase is rhombic and has properties in between the alpha and the gamma phases.

Iron ore slag

Introduction :

The process of preparing iron from its ores was discovered very early, certainly before the thirteen century B.C. perhaps the metal was found in the ashes of a fine built on a outcrop of iron ore, such as hematite, magnetite, or siderite.  The ore would have been reduced by charcoal at the high temperature of the fire to yield iron. Iron is produced in blast furnace by a similar reduction.

A mixture of iron ore, coke (carbon produced by heating coal), and lime stone is added at the top of the furnace, and a blast of heated air enters at the bottom.Near the bottom of the furnace, the coke burns to the carbon dioxide.  As the carbon dioxide rises to the heated coke, it is reduced to carbon monoxide. The carbon monoxide then reduces the iron oxides in the iron ore to metallic iron. The overall reduction of hematite can be written:
                         Fe₂O₃ (s) + 3CO(g) → 2Fe(l) + 3CO₂(g)

Description to iron ore slag

Molten iron flows at the bottom of the blast furnace, where it is drawn off.Impurities in the iron ore react with calcium oxide from the lime stone to produce a glassy material called slag. Molten slag collects in a layer floating on the molten iron and is drawn off periodically. Steals are alloys containing over 50% iron and up to about 1.5% carbon.The iron obtained from a glass furnace contains a number of impurities including 3% to 4% carbon, that make it brittle.

To produce steal, you must removed these impurities and slag and reduced the carbon contents of the iron.The basis oxygen process is a method of making steal by blowing oxygen into the molten iron oxidize impurities and decrease the amount of carbon present.Other metals may be added to the steal to give it desired properties.Stainless steels, for example, contain 12% to 18% chromium and 8% nikle.

Molten iron

Introduction :

Let us first be aware of the element iron, and then we can discuss more about molten iron. It is a chemical element with the atomic number 26 and its reperesentation is done by the formula 26. Mostly, it is available in the two forms, i.e., +2 and +3 oxidation states. It is one of the most common element which is available in plenty on the earth's crust. It is produced by the fusion of heavy metal elements mostly found on the surface of stars. Iron and its all form of alloys are regarded as the ferromagnetic elements.

Basically, molten iron is obtained in the blast furnace. Basic fetaure of blast furnace is that we need to remove oxygen as well as the impurities to obtain the iron in its pure form.

The various steps of blast furnace are as follows :
The main sources of iron ore are haematite(Fe₂O₃http://drupal.mathcontent.com/node/60928/edit) and magnetite(Fe₃O₄). 

(1) First of all, we need to add Charcoal, limestone, iron ore and coke from the top of the blast furnace.

(2) Next, the inserted charge gets heated and dried by the hot gases which is blown through the furnace.

(3) Thus, there is formation of the molten iron which starts melting down from the inside surface of the molten iron.

(4) As there is insufficient supply of oxygen in the blast furnace, so, mostly there is formation of carbon monoxide only.

(5) Thus, molten iron and slag is drawn out from the blast furnace on a periodic basis.
 

The various reactions of blast furnace are :
(1) 3Fe₂O₃ + CO -> CO₂ + 2Fe₃O₄  ( at a temp. of 850⁰F )

(2) Fe₃O₄ + CO -> CO₂ + 3FeO   ( at a temp. of 1100⁰F )

(3) FeO + CO -> CO₂ + Fe   or      ( at a temp. of 1300⁰F )
      FeO + C -> CO + Fe                     ( at a temp. of 1300⁰F )

(4) CaCO₃ -> CaO + CO₂

(5) C + O₂ -> CO₂ + Heat

Image of molten iron :

Applications of molten iron :

Molten iron is basically used in two kinds of applications :

(1) Metallurgical - It is used in the various engineering applications like construction of machinery tools, automobile parts, used as a pillar in the construction of buildings. Pure iron being very soft can't be used for these purposes, so mostly it is used in the form of steel which is quite hard and can be used for purposes.

(2) Iron is used as a catalyst in the various chemical processes like the production of ammonia in the Haber-Bosch process.

(3) Iron also has a biological importance as it is required by all the living organisms for their healthy growth.

Disadvantages of molten iron :

(1) Intake of high amount of iron content in the body can lead to the damage of body parts like DNA, proteins, lipids etc.

(2) There can be also damage to the cells of gastro-intestinal tract, coma and various heart related diseases.

Iron compounds

Introduction 

Iron has atomic number 26 and mass number 55.847.  Iron has oxidation states +2, +3.  Iron compound has electronic configuration [Ar] 4s², 3d⁶.  Iron belongs to d-block element group also called transition metal group.  Iron belongs to Group 8 and Period 4 in the periodic table.  Iron is the fourth most abundant element on earth and the most common ferromagnetic material in everyday use.  Fresh iron compound appear silvery gray.

In ancient days Iron was used but not before copper related alloys or bronze.  Pure iron is softer than aluminium but it is strengthened by adding impurities.  Iron compound is a strong metal which is widely used in construction purposes such as building houses, complex etc.  Steel is 1000 times stronger than iron.  Iron compound is smelted in blast furnace, where ore is reduced by coke to metallic iron.  Elemental iron is very reactive; it oxidizes in air to give iron oxide, also called as Rust.  Iron compounds form binary compounds with halogen and the chalcogens.

In organometallic chemistry, Ferrocene was the first sandwiched compound discovered.  Iron compounds forms complex with di oxygen as haemoglobin and myoglobin; these two compounds are very important common oxygen transport protein in vertebrate.  Iron oxide mixed with Aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ore.

Features of iron compounds

1)      Atomic radius and ionic radius of Group 8 elements: A.R. and I.R. increases down the group.

Elements	Fe	Ru	Os	Uno
A.R.  (pm)	126	134	135	-
I.R. (pm)	(+2)=77, (+3)=63	82	-	-

Where A.R.  (pm) = Atomic radius in pico meter.
              I.R.  (pm) = Ionic radius in pico meter.

2) Ionisation energy (I.E.) in Iron compound:
       1^st I.E.    =     759.3 KJ/mol.
       2^nd I.E.   =    1561.1 KJ/mol.
       3^rd I.E.    =    2957.3 KJ/mol.

3)      Non-metallic properties of Iron Compound: Iron is a metal which is a chemical element is good conductor of electricity and heat and forms cations with ionic bonds with non-metals.

4)      Melting points (M.P.) and Boiling points (B.P.) of Group 8 elements:

Elements	Fe	Ru	Os	Uno
M.P.  (0C)	1808	2810	3300	-
B.P.  (0C)	3023	4425	5300	-

5)      History of Iron compounds: Iron artifacts have been found around 3000 B.C.  A remarkable iron pillar dating about A.D.  400 is standing today in Delhi.

6)      Ores of iron compounds: Iron ores are rich in Iron oxide and vary in colour from dark grey, bright yellow, deep purple to rusty red.  The iron compound itself found in the form of

a)      Magnetite (Fe₃O₄).

b)      Hematite (Fe₂O₃).

c)      Goethite (FeO(OH))

d)     Limonite (FeO(OH).n(H₂O))

e)      Siderite (FeCO₃).

Hametite is a natural ore.  Hametite refers to early days mining.  The raw material used to make pig iron is iron ore.  The pig iron is the main raw material to make steel. 98% of mined ore is used to make steel.

Uses of Iron compounds: By adding impurities, Steel is produced.  Steel is widely used to make stainless steel plates and other various utensils.

Example of iron compounds: Iron 2 chloride

Iron 2 chloride is also called as Ferrous chloride. Its chemical formula is FeCl₂. Iron 2 chloride has high Melting point. It is a paramagnetic solid and is obtained in the form of an off-white solid. Iron 2 chloride crystallizes from water as the greenish tetrahydrate, which is used in laboratory uses and other applications. The compound is also soluble in water; aqueous solutions of Iron 2 chloride is yellow in color.
Molecular Formula of Iron 2 Chloride is FeCl₂. 4H₂O

Properties of Iron 2 chloride

Chemical properties:
 • Iron 2 chloride is Highily Corrosive substance.
• It readily causes burns.
• Inhalation of Iron 2 chloride is dangerous and touching with skin and swallowing of Iron 2 chloride is also harmful.
• Iron 2 chloride may lead to possible mutagen.

Physical properties:

• Specific gravity: 1.930g_n.
• Vapour  pressure: 10 mm @ 693 °C.

Appearance and odour:
Blue green crystals; readily oxidizes in solution

Preparation of iron 2 chloride

Wastes from steel production are made to treat with hydrochloric acid.  we get a hydrated form of Iron 2 chloride. When the hydrochloric acid is not completely consumed, such solutions are named as “spent acid,"
                             Fe + 2 HCl → FeCl₂ + H₂

Laboratory Preparation method:
Iron 2 chloride can be prepared by treating Iron powder with a solution of methanol and concentrated Hydrochloric acid under inert atmosphere. This reaction gives the methanol solvate, under vacuum heating to about 160°C gives anhydrous Iron 2 chloride.
Another laboratory method of synthesis of Iron 2 chloride is the treatment of FeCl₃ with Chlorobenzene

2 FeCl₃ + C₆H₅Cl → 2 FeCl₂ + C₆H₄Cl₂ + HCl
Preparation of Iron 2 chloride in this way shows convenient solubility in tetrahydrofuran, a commonly used solvent for the chemical reactions. In ferrocene, Wilkinson reactions generated Iron 2 chloride by heating FeCl₃ with iron powder. At high temperatures Ferric chloride decomposes to ferrous chloride.

Reactions of Iron 2 chloride

Iron 2 chloride forms complexes with many ligands. Iron 2 chloride when treated with two molar equivalents of [(C₂H₅)₄N] Cl to yield the salt [(C₂H₅)₄N] ₂[FeCl₄]. In the same way, some compounds also prepared are, [MnCl₄]²⁻, [MnBr₄]²⁻, [MnI₄]²⁻, [FeBr₄]²⁻, [CoCl₄]²⁻, [CoBr₄]²⁻, [NiCl₄]²⁻, and [CuCl₄]²⁻ salts.

Applications of Iron 2 chloride

Iron 2 chlorides is widely used in,

1. Preparation of Iron complexes.
2. In waste water treatment
3. Iron 2 chloride is used as a reducing flocculating agent in treatment with chromate containing waste water.  
4. In many of organic synthesis and reaction, Iron 2 chloride is used as a reducing agent.

Organic chemistry in life

Here was once a time when chemists thought "organic" referred only to things that were living, and that life was the result of a spiritual "life force." While there is nothing wrong with viewing life as having a spiritual component, spiritual matters are simply outside the realm of science, and to mix up the two is as silly as using mathematics to explain love (or vice versa). In fact, the "life force" has a name: carbon, the common denominator in all living things. Not everything that has carbon is living, nor are all the areas studied in organic chemistry—the branch of chemistry devoted to the study of carbon and its compounds—always concerned with living things.The element carbon forms a vast number of compounds. 

Over 16 million carbon-containing compounds are known, and about 90% of the new compounds synthesized each year contain carbon. The study of carbon compounds constitutes a separate branch of chemistry known as organic chemistry. This term arose from the eighteenth-century belief that organic compounds could be formed only by living systems. This idea was disproved in 1828 by the German chemist Friedrich Wöhler when he synthesized urea (H2NCONH2), an organic substance found in the urine of mammals, by heating ammonium cyanate (NH4OCN), an inorganic substance. Organic chemistry addresses an array of subjects as vast as the number of possible compounds that can be made by strings of carbon atoms.

Chemistry of Life

Life on earth depends on the chemical element carbon, which is present in every living thing. Carbon is so important, it forms the basis for two branches of chemistry, organic chemistry and biochemistry. The GED will expect you to be familiar with the following terms:

Hydrocarbons - molecules that only contain the elements carbon and hydrogen (e.g., CH4 is a hydrocarbon while CO2  is not)

Organic - refers to the chemistry of living things, all of which contain the element carbon

Organic Chemistry - study of the chemistry of carbon compounds involved in life (so, studying diamond, which is a crystalline form of carbon, isn't included in organic chemistry, but studying how methane is produced is covered by organic chemistry)

Organic Molecules - molecules that have carbon atoms linked together in a straight line (carbon chain) or in a circular ring (carbon ring)

Polymer - hydrocarbons which have chained together

Separation of organic compounds

Introduction

The Separation of a mixture of organic compounds to give the pure components is of the great practical importance in chemistry. Many synthetic reactions react to give mixture of products. It is necessary to have a reasonably clear idea of how the mixture of compounds can be separated out. Almost all the compounds which have the interest of biochemical occurs naturally as components of very complex mixture from which they can be separated out only with considerable difficulty and efficiency.

Separations of organic compounds can be achieved by differences in physical and chemical properties, such as differences in boiling point, melting point etc. or by chemical means, having differences in physical properties which are regulated by chemical reactions.

Problems in Separation of organic compounds

A common problem arises in organic chemistry involves the separation of a mixture of two or three organic compounds into single compound fractions followed by the purification and identification of each organic compound.  To effect the separation of organic compounds, the chemist must make use of the different properties of the components. The phenomena such as differences in solubility, density, acid-base chemistry and reactivity are used to separate a mixture of organic compounds.

Then each component is purified and identified.  For example the carboxylic acid can react with a base such as sodium hydroxide and forms an anion which is water soluble. The neutral doesn’t react and so it remains “neutral”. The possible organic neutral compounds are separated out.

Utility of Separation of organic compounds

It is important to note that single extractions of organic compound for its separation do not necessarily yield complete separations, and that multiple extractions sometimes needed. It includes the extraction the original organic solution two times with aqueous sodium hydroxide solution to remove the acid and water soluble impurities from the organic layers of mixture.

The two aqueous extracts are then combined with each other and set aside as the aqueous sodium hydroxide fraction. The organic compound is further extracted once with distilled water to remove any water soluble impurities.  Once these extractions of organic compound are complete, the organic solution should contain only the "neutral" compound.

Structural representations of organic compounds

Introduction

The structural formula of a chemical compound is a graphical representation of the molecular structure to show that how the atoms are arranged. The chemical bonding inside the molecule is shown, either explicitly or implicitly. There are three common representations which used in publications: text, Lewis type and line-angle formula. Also many other formats are used, as in chemical databases, like SMILES, InChI and CML.

Structural formulas give a representation of the molecular structure. Chemists mostly describe a chemical reaction or synthesis by using structural formulae instead of chemical names, because the structural formulas allow the chemist to observe the molecules and the changes that occur.

Many chemical compounds are present in different isomeric forms, which have different structures but the same overall chemical formula. A structural formula indicates the arrangements of atoms in a mannered way which a chemical formula cannot do.

Text formulas

In early organic chemistry publications, when use of graphics was strictly limited, a text-based system came for describing organic structures in a line of text. Although this system tends to break down with complex cyclic compounds, it remains a easier way to represent simple structures.

CH₃^–CH₂^–OH or CH₃CH₂OH

Lewis structures

Lewis structures are flat graphical formulas which show the atom connectivity, but do not give information about the three-dimensional structure of molecules. This notation is commonly used for small linear molecules. A single line shows a single bond or single electron pair. Two and three lines show double and triple bonds, respectively. Alternatively, dots (•) are used to show single electrons. This is called as Lewis Dot Structure.

Three-dimensional structures

Several methods are present to picturize the three-dimensional arrangement of atoms in a molecule.

Fischer projection

The Fischer projection is commonly used for linear monosaccharides. The vertical backbone is implicit to form a bridge-like structure on the paper plane with the substituents sticking up.

Perspective drawings of cyclic conformations

Perspective drawing is a three-dimensional perspective of a cyclic compound, also shows the structure of the ring, as it is an example a chair conformation.

Newman projection and sawhorse projection

The Newman projection and the sawhorse projection are used for depicting the stereochemistry at two connected carbon atoms.

Skeletal formulas

Skeletal formulas are the standard information for more complex organic molecules. Carbon (C) atoms are represented by the vertices (corners) and termini of line segments which are not marked with an atomic symbol. Each carbon atom is in turn thought to bear enough hydrogen atoms to give the carbon atom four bonds.

Stereochemistry in skeletal formulas

Chiral property in skeletal formulas is denoted by the Natta projection method. Solid or dashed wedged bonds symbolize bonds pointing above-the-plane or below-the-plane of the paper, respectively.