Man's physical universe



Ammonia is frequently combined with phosphoric acid to produce

important fertiHzers that supply the phosphorus that the soil needs in

Ammonia is also combined with sulfuric acid

addition to the nitrogen.

Sulfuric acid in this case acts as an inex-

to form ammonium sulfate.

pensive carrier for the ammonia. Ammonia gas may be readily liquefied;

in this form it is used extensively as a refrigerant in the manufacture

of ice. Ammonia will react with nitric acid to produce ammonium

nitrate, NH4NO3, used as a fertilizer and in making certain

types of blasting agents.

The E. I. du Pont de Nemours Company has recently developed a

practical process on a commercial scale for the production of sulfamic

acid, HSO3NH2, which has many interesting uses based upon its

unique properties. The ammonium salt of sulfamic acid is now used

Keep your eye on this

as a weed-killer and as a flameproofing agent.

product; it is sure to go places.

The Air Contains Rare Elements Which Are More Inert Than Nitrogen.

The rare gases, helium, argon, neon, krypton, and xenon, are sometimes

referred to as the old maids and bachelors of chemistry because

their chemical inactivity is their chief property. So inactive are these

elements that they do not combine to form diatomic molecules as most

gases do; their molecules consist of one atom only.

Helium is next to the lightest gas known, having a lifting power 92

per cent of that of hydrogen, but unlike hydrogen in that it is not

inflammable. The main source of helium is the natural-gas wells of

western United States. It is used for airships and for the prevention

and treatment of "bends," the disease of deep-sea divers and highaltitude

aviators. A mixture of helium and oxygen is used in treating

severe respiratory diseases such as acute asthma.

Neon and argon are used in gas-filled glow lamps.

Argon is also used

in filling electric-light bulbs, thus reducing the tendency of the hot

filaments to vaporize.

Argon and neon are obtained along with nitrogen and oxygen in the

fractional distillation of liquid air. Argon is present in air to the extent

of 0.94 per cent by volume. One part in 65,000 parts of air is neon,

while the other gases are present in such small proportions that they

are too rare to have important uses.


1. Discuss catalysis as to (a) definition, (b) the types of catalysts, (c) examples

of six different catalytic processes, and (d) the nature of catalysis.

2. Discuss physiological catalysts.

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