Calcium

by Nikki Longyear

You are probably wondering what a mole is exactly. Let me try to explain. A mole is a fixed number, similar to a dozen, which describes a number of particles as well as quantity of mass. The fixed number is called Avogadro’s number. Avogadro’s number value is 6.02 x 10 23. In one mole of calcium there are 6.02 x 10 23 atoms. I one moles of calcium there are also 40.08g. A mole is used as a conversion ratio in dimensional analysis. Mole can be used in converting to or from the atomic mass of an element, the atomic mass of an element, the formula mass of an ionic compound, the molecular mass of a molecular compound, or atoms and molecules.

Now that you know what a mole is, let me explain to you what calcium is. Calcium is a soft, silvery-white metallic element found most widely in such rocks as limestone and marble. It is fifth in abundance among the elements in the earth’s crust, but is not found uncombined in nature. I make up about 3 ½ per cent of the earth’s crust. I react readily with both oxygen and water. In cold, dry air, calcium is not readily attacked by oxygen, but when heated it unites vigorously with the halogens, oxygen, sulfur, phosphorus, hydrogen, and nitrogen. Calcium reacts violently with water forming the hydroxide Ca(OH)2 and releasing hydrogen. In nature I occur only in componds – chiefly as calcium carbonate (CaC03), calcium fluoride (CaFl2), and calcium sulfate (CaSO4).

I have an atomic number of 20 and atomic weight of 40.08g. My chemical symbol is Ca. I am in group 2 (or IIa) of the periodic table. I belong to the group of elements called alkaline earth metals. Calcium has six stable and several radioactive isotopes. As a malleable and ductile metal, I rapidly tarnish to yellow on exposure to air. I melt at about 839 C (about 1542 F) and boil at about 1484 C (about 2703 F). I have a density of 1.55 grams per cubic centimeter at 20 C.

Calcium and its compounds have many industrial uses. Pure calcium metal, used in certain kinds of alloys is obtained from molten calcium chloride through a process called electrolysis. Various industrial processes, such as leather tanning and petroleum refining, involve calcium oxide. This compound is prepared by heating calcium carbonate in furnaces called kilns. Calcium fluoride and calcium sulfate is used in making cement and plaster for constriction work. Manufacturers use other calcium compounds in a wide variety of products ranging from fertilizer to paint.

Calcium is essential to all living things. I am the most abundant metal in the human body. Calcium is vital for the growth and maintenance of the bones and teeth, and I help the blood to clot and the muscles to contract. A daily diet includes green vegetables, milk, and milk products supplies enough calcium for the human body’s normal needs.

Sir Humphry Davy, an English chemist, first isolated pure calcium in 1808 by means of electrolysis. However, the ancient Egyptians, Greeks, and Romans knew about calcium compounds and used them to make mortar.

Well, the sun is drifting into the horizon. It’s time for me to head back to the barn. I hope you can see how important calcium is to you.