Man's physical universe

xanabras

UNIT IX

SECTION 1

OXYGEN AND SULFUR, CARBON AND SILICON ARE

IMPORTANT ELEMENTS IN NATURE'S CHEMICAL

STOREHOUSE

Introduction.

Two pairs of nonmetals, representing two families of

the periodic

table, namely, oxygen and sulfur, carbon and silicon, are very abundant,

cheap raw materials, whose increasing use is so modifying our

environment that they may be used as yardsticks for gauging the extent

of the industrialization of modern civilization. Silicon is the only one

of these elements that does not occur in large amounts in the uncombined

state.

Free silicon has few uses, but the compounds of silicon,

such as sand, gravel, clay, and stone, rank next to coal

in the tonnage

of their production.

A recent study has shown that water, air, coal, and sulfur are needed

most frequently in preparing the 150 most important heavy (bulk)

chemicals used in modern industry.

Oxygen Is the Most Abundant Raw Material.

Among all the elements oxygen stands first in abundance.

Not only

is oxygen found in the atmosphere in the free state to the extent of

about 21 per cent by volume, but it is also found in the combined state

as water, H2O, sand, Si02, and in the majority of the materials which

make up the earth's crust. Nearly two thirds of the human body is

oxygen. Oxygen constitutes about 50 per cent of all of the known

material of our world, including its atmosphere, hydrosphere, and

lithosphere.

For commercial purposes the air generally serves as a source of oxygen,

inasmuch as the other gases in the atmosphere are inert.

When

relatively pure oxygen is needed, it may be prepared by the fractional

distillation of liquid air, while still purer oxygen is obtained by the

electrolysis of water. Air and water are the two most important industrial

raw materials. Oxygen is referred to as the "breath of industry."

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