Andrew Richard Bliss.

A text book of physics and chemistry for nurses online

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animals and plants obtain oxygen necessary for their existence
from that found dissolved in water. It is about sixteen times as
heavy as hydrogen.

Oxygen is very active, uniting with all elements except fluorine.
When the union of oxygen with an element or compound is accom-
panied by an evolution of light and heat, the process is known as
combustion ; if the reaction is less energetic, no light being evolved,
it is called " slow combustion " or oxidation. Those substances
which are easily oxidized are called " combustible." They are
composed mainly of hydrogen and carbon, with which the oxygen
unites, forming water and carbon dioxide, CO 2 .


Oxygen is essential to the life of plants and animals. An adult
consumes about two pounds daily. Animals use more oxygen
than plants. Plants give off more oxygen than they use. How-
ever, animals exhale carbon dioxide, which is made use of by
plants. The carbon dioxide and water given off by the lungs are
produced by the oxidation of the tissues by means of the oxygen
inhaled and carried throughout the body by the blood.

The gas is extensively used as an inhalant for stimulating the
action of the heart in diseases of the lungs, in dangerous chloro-
form narcosis, and poisoning by coal gas.

Experiment 9. Mix well 5 grammes of potassium chlorate and man-
ganese dioxide and evenly distribute the mixture on the side of a horizontal
test-tube fitted with a one-hole stopper and glass tube as in the case of the
hydrogen experiment. Collect a bottle of oxygen gas, place it right side up,
covering the mouth of the bottle with a wet paper. Insert a dry, unlighted
taper. No activity is noticed. Then insert a glowing stick and note the rapid
burning which ensues. This illustrates the activity of oxygen at higher


Formula, Os. Molecular weight, 47.64.

Ozone is a peculiar form of oxygen found in small quantities
in the air, especially after thunder-storms, and in the region of
electrical machinery. It is colorless, and has a peculiar odor.
Its properties are practically the same as those of ordinary oxygen,
but it is much more active chemically.


This group is composed of the elements chlorine, bromine,
iodine, and fluorine. They are known as " halogens " because
of their salt-forming properties. They can be derived from sea-
water and sea-plants. All members of the group have sharp,
acrid tastes and characteristic odors. They are corrosive and are
employed as bleaching and disinfecting agents,


Symbol, Cl. Atomic weight, 35.18. Valence, I, III, V, VII.

Chlorine never occurs in nature in the free state, but is widely
distributed in combination as chlorides, common salt (sodium
chloride, NaCl) being the most abundant.



A laboratory method for its preparation is the oxidation of
hydrochloric acid:

4 HC1 + Mn0 2 = CU
Hydrochloric Manganese Chlorine
acid dioxide

Manganese Water

Chlorine is a gas having a greenish-yellow color, a penetrating,
suffocating odor, and an acid taste. It is heavier than air, and
dissolves readily in water. The solution of chlorine gas in water
is known as " Chlorine Water."

Chemically, chlorine is very active, especially with the metallic
elements and hydrogen. In the pres-
ence of water, chlorine is an active
bleaching agent, because of the oxygen
gas that is liberated through the de-
composition of the water. For this
reason it is also a good disinfectant.

Experiment 10. Place 10 grammes of
manganese dioxide in the flask used for the
hydrogen experiment and lead the delivery
tube into a dry bottle, right side up. Have
the tube extend to the bottom of the bottle.
Add 25 mils of hydrochloric acid to the man-
ganese dioxide and warm (Fig. 37) . Chlorine
gas is liberated, and, since it is greenish-yellow,
one may easily tell when the bottle is full of the
gas. [Caution: Do not breathe the gas, as it is
very irritating to the mucous membranes of the
nose and throat.] Place a red or other colored flower in the bottle and note the
bleaching effect of the gas. Repeat with a small piece of damp, colored calico.


Symbol, Br. Atomic weight, 79.34. Valence, I, III, V, VII.
Bromine does not occur in the free state in nature, but is
found in combination, as bromides, along with the chlorides.

The element may be liberated from its compounds, the bro-
mides, by treating a solution of a bromide, like potassium bromide
(KBr), with chlorine gas. The chlorine, because of its greater
affinity for the metal, replaces the bromine, as shown in the follow-
ing equation:

KBr + Cl = KC1 + Br

Potassium bromide Chlorine Potassium chloride Bromine

FIG. 37.


Bromine is a caustic, reddish-brown, fuming liquid, having an
odor resembling that of chlorine. It is heavier than water, and
dissolves in twenty-eight parts of the solvent, the solution being
known as "Bromine Water." It is more soluble in chloroform,
ether, and carbon disulphide.

Although bromine is quite energetic, it is less active than
chlorine, but is more active than the next member of the group,
iodine. Its chemical properties are very similar to those of chlorine.

The chief use of the element is in the manufacture of the
bromides, although it is a disinfectant.


Symbol, I. Atomic weight, 125.89. Valence, I, III, V, VII.

Iodine occurs in combination in the ashes of sea-weed and in
the mineral " Chili-saltpetre " (NaNO 3 ), never in the free state.

It may be liberated from its com-
pounds the iodides. Example :

KI - + Cl r =

Potassium iodide Chlorine

KC1 + I

Potassium chloride Iodine

It comes in the form of bluish-
black, volatile plates, with a metallic
lustre, a characteristic odor, and a
sharp, acrid taste. It is about five
times as heavy as water. Upon heat-
ing, it is converted to violet vapors.
The element is slightly soluble in water,
readily soluble in alcohol, ether, chloro-
form, carbon disulphide, and aqueous
solution of potassium iodide. Tincture
of Iodine is an alcoholic solution con-
taining about 7 per cent, of iodine and
5 per cent, of potassium iodide.

Although it attacks some metals, it is the least energetic of
this group. Solutions of iodine should not be handled in silver
spoons, since it attacks this metal. It stains the skin brown,
Starch paste is turned blue by free iodine,

FlG -


Its use in medicine is that of an antiseptic and disinfectant.

Experiment u. Place about 3 grammes of potassium iodide, an equal
quantity of manganese dioxide, and 15 mils of 50 per cent, sulphuric acid
into a small Erlenmeyer flask and mix well. Fold a small filter paper as for a
funnel, wet it with cold water and place it, point up, over the mouth of the
flask (Fig. 38). Warm the flask gently. The iodine will be deposited on the
inside surface of the filter paper as thin plates. Test its solubility in alcohol
and water.


Symbol, F. Atomic weight, 19.0. Valence, I.

Fluorine occurs in combination in certain minerals, sea-water,
mineral waters, bones, teeth, and milk.

It is a yellowish gas with a penetrating odor, and is the most
active of all known elements. It is prepared by electrolytic
processes, and must be kept in vessels of gutta-percha, platinum,
or gold.

Symbol, N. Atomic weight, 13.93. Valence, III, V.

In the free state nitrogen constitutes about four-fifths of the at-
mosphere. It occurs in combination in many minerals, all animal
substance, and forms a component of the products of animal decay.

Nitrogen is a colorless, odorless, tasteless gas, a little lighter
than air. It is slightly soluble in water. Nitrogen does not burn
or support combustion. It is chemically inert. Its compounds
are unstable and, upon decomposition, often explode, as in nitro-
glycerin. Some are essential to the growth of plants and animals.
Many very poisonous compounds contain nitrogen, such as the
cyanides. The gas itself is non-poisonous and simply acts as a
diluent for the oxygen in the air, without which, oxidation
processes in the body would be far too rapid.


The atmosphere is a mechanical mixture of gases and forms the
aerial envelope of the earth. The average composition of dry
air is as follows :

Nitrogen 78.10

Oxygen 21.00

Argon 0.90

Helium, neon, krypton, xenon,
carbon dioxide, and hydrogen. . . traces


The nitrogen serves as a diluent for the life-sustaining oxygen.
The oxygen supports life, combustion, and oxidation, and remains
practically constant, due to liberation of oxygen from plants.
Carbon dioxide is found in variable quantities, since it is a product
of combustion, fermentation, decay, and respiration. It averages
about 0.04 per cent., but is higher in cities. In living-rooms it
should not rise above o.i per cent. Another variable constituent
of the atmosphere is moisture. The rare gases helium, neon,
krypton, and xenon, as well as hydrogen, occur only in traces.

Air may be liquefied on a commercial scale by machinery.
When in the liquid state it is faintly blue and begins to boil at
190 C. It freezes metallic mercury. It has been used to a
limited extent in medicine as a caustic and as a local anaesthetic.

Symbol, S. Atomic weight, 31.83. Valence, II, IV, VI.

Sulphur was one of the elements known to the ancients. It
occurs in the free state in very large quantities, especially in the
neighborhood of volcanoes. It also occurs in combination as
sulphides and sulphates.

It is extracted from native sulphur by fusion and subsequent

Sulphur is a lemon-yellow, brittle, crystalline solid, odorless
and almost tasteless. Its specific gravity is 2.05. It is insoluble
in water, but readily dissolves in carbon disulphide, turpentine,
fixed oils, etc. It melts at 114.5 C. The melted liquid is first
straw-yellow, but becomes dark red and viscid when heated to
about 250 C.; then it becomes too thick to pour and almost
black in color. When heated to the boiling-point, 448.4 C., it
becomes thin again, but remains dark in color. It exists in an
amorphous form and two different crystalline forms.

Experiment 12. Slowly heat some sulphur in a dry test-tube until it
boils, noting the various changes already described. Then pour out the
melted substance into a dish of cold water. Examine the mass in the dish.
Also examine the remains in the test-tube.

The commercial forms of sulphur are: (a) roll sulphur or
brimstone, a crude, moulded form used for commercial purposes


only; (6) flowers of sulphur or sublimed sulphur ("Sulphur Subli-
matum"), prepared by allowing the vapors of sulphur to cool in
cold chambers; (c) washed sulphur ("Sulphur Lotum"), prepared
by washing sublimed sulphur with a diluted solution of ammonia
gas; (d) precipitated sulphur ("Sulphur Praecipitatum") or milk of
sulphur, prepared by boiling together sulphur, slaked lime, and
water, and then adding to this solution, hydrochloric acid, which
precipitates the sulphur.

Sulphur burns with a blue flame, giving off suffocating fumes
of sulphur dioxide (S0 2 ). It combines with most of the metals
and non-metals.

It is used for vulcanizing, in the manufacture of gunpowder
and fireworks, and in medicine as a laxative and parasiticide.

Symbol, P. Atomic weight, 30.75. Valence, III, V.

Phosphorus is never found in the free state in nature. Its
principal occurrence is in combination as a phosphate in minerals
and bones, from which it is prepared.

It occurs in a number of different forms, the principal ones
being those known as the red and the yellow varieties.

Yellow phosphorus occurs in the form of a waxy, translucent
solid with a garlic-like odor. Specific gravity, 1.83. It melts at
44 C. It is insoluble in water, but is quite soluble in chloroform,
carbon disulphide, and oils. It unites very readily with oxygen,
and therefore must be kept under water to prevent combustion.
The slow oxidation of phosphorus is accompanied by a glowing
which is known as "phosphorescence." It unites directly with
all elements except nitrogen and carbon.

Red phosphorus, also known as " amorphous phosphorus,"
may be prepared from the yellow by heating to 300 C. in air-
tight vessels. Its specific gravity is 2.14. It is reconverted to
ordinary yellow phosphorus by heating to 260 C. It is stable
in air, does not phosphoresce, and is insoluble in carbon disulphide
and other solvents. Red phosphorus is much more inert than the
yellow variety.


The yellow variety is very poisonous, although the red is com-
paratively non-toxic because of its insolubility. Yellow phosphorus
is used in medicine for building up bony tissue in children. It
is also used as a rat poison. The red variety is used in the manu-
facture of matches.

Experiment 13. Place a small piece of phosphorus, a piece about the
size of a pea, in a dry dish in a moderately warm room and watch the result
after a few minutes. The burning of the phosphorus shows its great affinity
for oxygen. The^white fumes given off consist of phosphorus pentoxide


Symbol, B. Atomic weight, 10.9. Valence, III.

Boron does not occur in the free state, but is found natively
as borax (Na 2 B 4 O7) and boric acid (HaBOs).

It may exist as a brown or yellow, amorphous powder, or in
the form of infusible crystals. The crystalline variety possesses a
degree of hardness which stands next to that of the diamond.


Symbol, Si. Atomic weight, 28.2. Valence, IV.

Next to oxygen, silicon is the most abundant of the elements.
It is never found free, but occurs combined in nearly all rocks and
soil, as well as in plant and animal life.

It is a dark, lustrous, hard solid, with a specific gravity of 2.5.
It exists in both amorphous and crystalline forms.


Symbol, C. Atomic weight, 11.9. Valence, IV.

Carbon occurs abundantly both in the free and combined
condition. In the free state it is found in three forms : (a) amor-
phous, (b) graphite, (c) diamond.

Amorphous carbon includes coke, wood charcoal, animal
charcoal, and lampblack. Coke is the non-volatile residue left
in the manufacture of illuminating gas from coal. It occurs as
an irregular, brittle, porous, grayish, lustrous solid. Wood char-
coal, usually called simply " charcoal," is obtained by burning
wood with little air. It is a black, porous solid without odor or


taste. Animal charcoal or " bone-black " is prepared by the
destructive distillation of bones. Lampblack is prepared through
the ignition of compounds rich in carbon and yielding smoky
flames, like resins.

Graphite, called " plumbago " or " black lead," occurs as a
native, crystalline variety, and is also made from amorphous
carbon by means of the electric current. It occurs in the form of
friable, black, metallic-like masses. When rubbed between the
fingers a greasy feeling is experienced, and it leaves a black line
when run over paper.

Diamond is the hardest known substance. Its specific gravity
is 3.5. It crystallizes in cubes. When diamonds are found they
are covered with an opaque layer, which is removed when the gem
is cut and polished. The brilliancy of the diamond depends upon
the high_ refraction of light and the large number of reflecting
surfaces. Microscopic diamonds are sometimes found in steel.

At high temperatures all varieties of carbon unite with oxygen
of the air to form carbon dioxide (CC^). Carbon is practically
inactive with all other substances at ordinary temperature.

Coke and charcoal are used as fuel. Lampblack is used as a
paint pigment. Animal charcoal is used as a deodorizer and de-
colorizer. Graphite is employed in the manufacture of lead pencils,
anti-friction compounds, paint, glazing, and electrotyping. Dia-
monds are worn as gems; small imperfect ones are used in glass-
cutters and drills.

Coal contains carbon, oxygen, hydrogen, nitrogen, mineral
matter, and frequently sulphur. There are two kinds: Anthracite
and Bituminous. The former is hard, and contains about 90 per
cent, of carbon and very little sulphur. It burns with little flame
and gives out an intense heat. There is but from 6 to 7 per cent,
of volatile matter in it. The latter is softer and contains from 10
to 30 per cent, of volatile matter.



THIS class of compounds is usually strongly acid in reaction,
reacts with metals and bases to form salts, has a sour taste, and
contains hydrogen as one constituent. Some give off fumes at
ordinary temperature, such as hydrochloric, nitric, and hydriodic
acids (HC1, HNO 3 , HI). They owe their physiological action to
the hydrogen atoms they contain. Upon coming in contact with
organic tissue they abstract water, coagulate the proteids of the
skin, and give rise to numbness and a stiff, puckery feeling. In
fevers they are employed internally, in much diluted condition,
to diminish thirst, because they stimulate the flow of saliva and
other alkaline fluids. They are excreted from the body chiefly
as ammonium salts. When administered in large doses or when
in undiluted condition they are caustic protoplasmic poisons.


These are colorless gases with sharp, irritating odors and acid
tastes. All are monobasic.


"Muriatic Acid "

This is the most important of the halogen acids. It is found
free in the atmosphere about volcanoes, and in human gastric juice.
It may be prepared by the action of sulphuric acid on sodium

2NaCl + H 2 SO = 2HC1 -f N a2 SO 4

Sodium chloride Sulphuric acid Hydrochloric acid Sodium sulphate

It is a colorless gas, with a sharp, irritating odor and acid
taste. It is heavier than air and very soluble in water. One volume
of water dissolves 505 volumes of the gas. This solution is com-


mercially known as " Concentrated Hydrochloric Acid." The
yellow color that some samples of this acid possess is due to the
presence of iron. The official diluted hydrochloric acid should
contain from 9.5 to 10.5 per cent, of the gas.

With metals and bases it gives rise to the formation of a
class of salts called " chlorides," such as sodium chloride, NaCl
(common salt) ; potassium chloride, KC1 ; calcium chloride, Ca
C1 2 ; ammonium chloride, NH 4 C1.

Hydrochloric acid may be identified by the white fumes
(ammonium chloride, NH 4 C1) that appear when a rod, moist-,
ened with ammonia water, is brought over the mouth of the
bottle containing it.

It is used in medicine to replace deficiency in the normal
acidity of the stomach, and as an antiseptic to prevent certain
forms of fermentation in the stomach.

Experiment 14. Place 10 grammes of sodium chloride in a flask fitted
with a two-holed rubber stopper and carrying a funnel tube and a bent glass
tube leading into a dry bottle. Through the funnel tube pour about 10 mils
of sulphuric acid and warm the flask. Hydrochloric acid gas is liberated.
Cautiously note the odor. Do not inhale the undiluted gas! The solubility of
the gas may be easily shown by pouring a small quantity of water into the
bottle, holding the palm of the hand firmly over its mouth, and shaking. The
gas will be dissolved by the water, creating a suction on the palm of the hand.
Hold a rod moistened with ammonia water over the bottle and note result.


Hydrobromic acid is a heavy, colorless gas with a sharp,
irritating odor and an acid taste. It is very soluble in water (600
to i ) . The official diluted hydrobromic acid contains from 9.5 to
10.5 per cent, of the acid.

Chlorine decomposes the acid according to the following
equation :

HBr + Cl = HC1 + Br

Hydrobromic acid Chlorine Hydrochloric acid Bromine

Its salts are known as " bromides," such as sodium bromide

When heated with strong sulphuric acid, the acid gives off
reddish fumes.

It is used as a sedative like its salts the bromides.



This is also a colorless, heavy gas, with a sharp, irritating odor
and an acid taste. It is very soluble in water (425 to i). The
official diluted acid contains from 9.5 to 10.5 per cent, of the acid,
and the syrup about i per cent.

Chlorine decomposes it according to the following equation:

HI + Cl = HC1 + I

Hydriodic acid Chlorine Hydrochloric acid Iodine

Its salts are known as " iodides," such as potassium iodide (KI).

The acid may be detected by adding some chlorine water and
starch paste, when a blue color will appear.

It is used in the treatment of asthma, syphilis, and some skin


Hydrofluoric acid is a colorless gas, which liquefies to a colorless
liquid at 19.4 C. It reacts with glass, its effect being known as
" etching. 1 ' For this reason it must be kept in gutta-percha or
wax bottles. It is very caustic, and, when brought in contact
with the skin, produces slow-healing ulcers.

Its salts are known as " fluorides," as sodium fluoride (NaF).

Its principal use is in the etching of glassware.


This acid is not known in the free state, but occurs in solution
in water. It may be manufactured by passing sulphur dioxide
(SO 2 ) into water.

SO 2 + H 2 O = HaSOi

Sulphur dioxide Water Sulphurous acid

It is dibasic. The acid is a colorless liquid with a sulphurous
odor and an acid, sulphurous, astringent taste. It should contain
6 per cent, of sulphur dioxide gas.

Its salts are known as "sulphites," as sodium sulphite (Na 2 SO 3 ) .

It is used as a bleaching agent, for removing fruit-juice stains
from linen, and as a disinfectant.



" Oil of Vitriol "

Sulphuric acid is the most important and powerful of the
mineral acids. It is found in springs and rivers that find their
origin in volcanic regions. In combination it is found as sulphates.

The acid is prepared by a process known as " The lead chamber
process," and also by the more modern " Contact process," in
which finely-divided metallic platinum is used as a " catalytic

The concentrated acid is a colorless, odorless, oily, very corro-
sive liquid having a specific gravity of 1.84. The official diluted
acid should contain 10 per cent, of the compound. It has a great
attraction for water and breaks up organic matter containing
hydrogen and oxygen, removing these elements in the form of
water. The carbon of the compounds is left behind, giving the
residue a black color. This is known as the " charring " action
of this acid.

The salts of this acid are known as " sulphates." Since the
acid is dibasic, it may form acid and double as well as neutral salts.
Examples: Na 2 SO 4 , sodium sulphate; NaHSO 4 , sodium acid
(bi- or hydrogen) sulphate; NaKSO 4 , sodium potassium sulphate.

It is used principally in chemical industry and manufacture.

" Sulphuretted Hydrogen " " Hydrogen Sulphide "

This acid occurs in volcanic gases, mineral waters, and as a
product of animal decomposition.

The acid may be prepared by treating a sulphide with diluted
sulphuric or hydrochloric acid.

FeS -f H 2 S0 4 = HjS + FeSO 4

Ferrous Sulphuric Hydrosulphuric Ferrous
sulphide acid acid sulphate

It is a colorless gas, with an odor of rotten eggs and a sweetish

taste. It is soluble in water, heavier than air, and burns with a

pale-blue flame. If the gas is inhaled in the undiluted condition,

it acts as a violent poison. Even in diluted condition it causes



nausea, headache, and dizziness. It tarnishes silverware, forming
a black layer of silver sulphide (Ag 2 S). Its salts are known as
" sulphides," such as ferrous sulphide (FeS). It is used as a
chemical reagent in the laboratory.



Nitrous acid is a very unstable, blue liquid, made by passing
nitrogen trioxide (^Os) into ice water.

N 2 O 3 + H 2 O = 2HNO,

Nitrogen trioxide Water Nitrous acid

Its salts are known as " nitrites," as sodium nitrite (NaNO 2 ).


"Aqita Fortis "

This acid is not found in the free condition, but occurs in com-
bination as nitrates. It may be prepared by treating a nitrate
with sulphuric acid.

2NaNO s + H 2 Sp4 = . 2 HNO S . + Na 2 SO 4
Sodium nitrate Sulphuric acid Nitric acid Sodium sulphate

Nitric acid is a colorless, fuming, very corrosive liquid, having
a specific gravity of 1.5. It is quite soluble in water. The official
acid should contain from 67 to 69 per cent, of the acid.

It readily yields up its oxygen, and is therefore known as a

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Online LibraryAndrew Richard BlissA text book of physics and chemistry for nurses → online text (page 5 of 17)