Iron

By

Brenna Visintin

First, I should probably explain to you what a mole is. Yes, I am a mole - in the animal sense that is. But there is a scientific term "mole" used in chemistry. A mole refers to amount of substance. It describes a number of particles (number of atoms or molecules) or a quantity of mass (atomic mass of element, formula mass of ionic compound, or molecular mass of molecular compound). For example, in one mole of iron there are 6.02 x 10²³ atoms. This number 6.02 x 10²³ is known as Avogadro’s number.

I’ll start out with basic facts about iron. Iron is a silvery-white solid metal in its elemental state. It appears in Group VIIIB of the periodic table in the lowered block of the table that contains the transition metals. The symbol of the element iron is Fe. It is derived from the Latin word ferrum, meaning iron. The atomic number of iron is 26, and its atomic weight is 55.847. The melting point of iron is 1535ºC, and the boiling point is 3000ºC. At 20ºC, iron has a density of 7.874 grams per cubic centimeters. In the hardness scale, iron is in Group V which means it can be cut with a sharp knife but only with great difficulty. Like other metals, iron can be hammered into thin sheets or drawn out into fine wires. It is also easily magnetized but loses its magnetism when removed from the magnetic field.

Chemically, iron is a fairly reactive metal. Iron has oxidation states of +2 and +3 and forms two types of salts: ferrous and ferric. In ferrous compounds, iron has a valence of +2, and in ferric compounds, iron has a valence of +3. Probably the most important, and least desirable, chemical reaction of iron is the reaction between iron, water, and oxygen to form hydrated iron oxide, better known as rust.

Iron is the fourth most abundant element in the Earth’s crust, making up about 5%. It is the second most abundant metal after aluminum. The molten core of the Earth is primarily elemental iron. Iron has four natural isotopes having masses of 54, 56, 57, and 58. Iron occasionally occurs naturally in its uncombined form but is abundant in combination with other elements. Iron ores are naturally occurring compounds of iron from which the iron can be extracted in large amounts. The main ores from which iron is obtained include hematite, magnetite, limonite, pyrite, siderite, and taconite. Hematite and magnetite are the richest iron ores and contain about 70% iron. Pyrite is probably one of the most interesting iron ores. It is better known by its name of "Fool’s Gold." It’s shiny, metallic appearance can fool people into thinking that it is gold!

Iron can be classified as pig iron, cast iron, or wrought iron. Pig iron is produced in a blast furnace and contains about 93% iron, 3% carbon, and smaller amounts of other elements. Today, most pig iron is used in making steel. Cast iron is an iron alloy that contains carbon and silicon. Due to its hardness, low cost, and ability to absorb shock, it is an important construction material. Wrought iron is nearly pure iron mixed with a glass-like material. It was once used in making many products now made from steel. You probably noticed me mentioning steel a lot. Well, steel is made from purifying iron and alloying it with other metals. There are several kinds of steel. Carbon steel in the most widely used kind of steel. It is made into many products such as structural beams, used in my field of work, automobile bodies, and kitchen appliances. Stainless steel resists corrosion better than any other steel. Household kitchen items, automobile parts, and hospital equipment are all made of stainless steel. Tool steel is used in metalworking tools, which are used in the field of construction.

Iron is also biologically important. It is an essential element for the proper functioning of all humans and all other invertebrate animals. Iron is a component of hemoglobin and myglobin molecules. Hemoglobin in red blood cells is responsible for the transportation of oxygen from the lungs to body cells and carbon dioxide from the cells to the lungs. Myglobin transports and stores oxygen for use during muscle contraction. Iron is also a component of some metabolic enzymes. Iron that is not in use in the body is stored in the liver, the spleen, and bone marrow. A lack of iron results in iron-deficiency anemia.

Hopefully I have not bored you with my lecture on iron. Iron is a very important part of our world today. So much for the dumb construction worker stereotype, eh?