Phosphorus is a highly combustible solid and in the pure
state it is exceedingly poisonous. In combination in the form
of phosphates, it is essential to every living cell in the body
and must be supplied to the body by such foods as contain
the phosphates in a form in which the body can assimilate
them. Among these foods are meat, milk, egg yolk, wheat,
grains, and the legumes.
Organic and Inorganic Matter. — All matter may be
classified as organic or inorganic. All organic substances
contain carbon. All substances that are formed during the
processes of life are organic and, as before stated, great num-
bers of carbon compounds have been artificially prepared.
NOTE. — Student make a list of eight organic substances.
NOTE. — Student make a list of eight inorganic substances.
Chemical Symbols. — In writing the names of elements it
is often inconvenient to write the full name, hence the ele-
ments are designated by their initial letters, or by those of
their Latin names. These abbreviations are called symbols
and represent one atom of the element and its combining
weight.
SYMBOLS OF THE ELEMENTS FOUND IN THE HUMAN BODY
1. Oxygen . . . . O 5. Calcium Ca
2. Carbon . . . . C 6. Phosphorus . . . . P
3. Hydrogen . . . . H 7. Potassium . . . . K
4. Nitrogen . . . . N 8. Sulphur S
6 DOMESTIC SCIENCE
9. Sodium . . . . Na 13. Iodine I
10. Chlorine . . . Cl 14. Fluorine F
11. Magnesium . . Mg 15. Silicon Si
12. Iron ...... Fe
Chemical Formulas and Equations. — The combination of
symbols which represents the elements found in a molecule
of a compound is called a chemical formula. H20 is the
formula for a molecule of water, water being composed of
two parts by volume of hydrogen and one part of oxygen.
C02 is the formula for carbon dioxide, which is composed of
one part by volume of carbon and two parts of oxygen.
When a substance undergoes a chemical change, or when
two or more elements or compounds unite chemically, these
changes may be represented by means of symbols or formulas
in the form of an equation :
H2 + 0 = H20
C + 02 = C02
C +0 = CO (Carbon Monoxide)
CHAPTER II
AIR AND COMBUSTION
Air. — Air is necessary for the support of life and combus-
tion. It is a mixture, not a compound; that is, the sub-
stances of which it is composed are not chemically combined.
It has definite weight. At the sea level the atmosphere
exerts a pressure of fifteen pounds on every square inch of
surface, but as the pressure is equal in every direction, we
are not crushed by this weight.
Air is composed of about one-fifth oxygen and four-fifths
nitrogen. There are present also varying amounts of car-
bon dioxide (C02), watery vapor, ammonia, dust, bacteria,
etc. The nitrogen is not in a form in which it can be util-
ized by either plants or animals. Upon the roots of certain
plants, as clover, peas, beans, etc., are found nodules contain-
ing bacteria which have the power of taking nitrogen from
the air and changing it to such compounds of nitrogen as
can be utilized by the plant. From these compounds the
plant builds complex nitrogenous compounds which it stores
in its cells as protein.
The oxygen in the air supports combustion.
EXPERIMENT 1. — Light a splint and insert it in a dry, empty
test tube. Is the flame extinguished ? Why ?
Page 3
Presented as published in 1913. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
AI-modernized reading of the original text
Phosphorus is a highly combustible solid and in the pure state it is exceedingly poisonous. In combination in the form of phosphates, it is essential to every living cell in the body and must be supplied to the body by such foods as contain the phosphates in a form in which the body can assimilate them. Among these foods are meat, milk, egg yolk, wheat, grains, and the legumes.
Organic and Inorganic Matter. — All matter may be classified as organic or inorganic. All organic substances contain carbon. All substances that are formed during the processes of life are organic and, as before stated, great numbers of carbon compounds have been artificially prepared.
NOTE. — Student make a list of eight organic substances. NOTE. — Student make a list of eight inorganic substances.
Chemical Symbols. — In writing the names of elements it is often inconvenient to write the full name, hence the elements are designated by their initial letters, or by those of their Latin names. These abbreviations are called symbols and represent one atom of the element and its combining weight.
SYMBOLS OF THE ELEMENTS FOUND IN THE HUMAN BODY
1. Oxygen . . . . O 5. Calcium Ca
2. Carbon . . . . C 6. Phosphorus . . . . P
3. Hydrogen . . . . H 7. Potassium . . . . K
4. Nitrogen . . . . N 8. Sulphur S
9. Sodium . . . . Na 13. Iodine I
10. Chlorine . . . Cl 14. Fluorine F
11. Magnesium . . Mg 15. Silicon Si
12. Iron ...... Fe
Chemical Formulas and Equations. — The combination of symbols which represents the elements found in a molecule of a compound is called a chemical formula. H20 is the formula for a molecule of water, water being composed of two parts by volume of hydrogen and one part of oxygen. CO2 is the formula for carbon dioxide, which is composed of one part by volume of carbon and two parts of oxygen.
When a substance undergoes a chemical change, or when two or more elements or compounds unite chemically, these changes may be represented by means of symbols or formulas in the form of an equation :
H2 + 0 = H20 C + 02 = C02 C +0 = CO (Carbon Monoxide)
CHAPTER II
Air. — Air is necessary for the support of life and combustion. It is a mixture, not a compound; that is, the substances of which it is composed are not chemically combined.
It has definite weight. At the sea level the atmosphere exerts a pressure of fifteen pounds on every square inch of surface, but as the pressure is equal in every direction, we are not crushed by this weight.
Air is composed of about one-fifth oxygen and four-fifths nitrogen. There are present also varying amounts of carbon dioxide (C02), watery vapor, ammonia, dust, bacteria, etc. The nitrogen is not in a form in which it can be utilized by either plants or animals. Upon the roots of certain plants, as clover, peas, beans, etc., are found nodules containing bacteria which have the power of taking nitrogen from the air and changing it to such compounds of nitrogen as can be utilized by the plant. From these compounds the plant builds complex nitrogenous compounds which it stores in its cells as protein.
The oxygen in the air supports combustion.
EXPERIMENT 1. — Light a splint and insert it in a dry, empty test tube. Is the flame extinguished ? Why ?