Practical
attempts to improve the refining of ores and their extraction to smelt metals
was an important source of information for early chemists in the 16th century,
among them Georg Agricola (1494–1555), who
published his great work De re metallica in 1556. His work describes the highly
developed and complex processes of mining metal ores, metal extraction and
metallurgy of the time. His approach removed the mysticism associated with the
subject, creating the practical base upon which others could build. The work
describes the many kinds of furnace used to smelt ore, and stimulated interest
in minerals and their composition. It is no coincidence that he gives numerous
references to the earlier author, Pliny the Elder and his Naturalis
Historia. Agricola has been described as the "father of
metallurgy".
In 1605, Sir Francis Bacon published The Proficience and Advancement of
Learning, which contains a description of what would later be known as
the scientific method. In 1605, Michal Sedziwój publishes the
alchemical treatise A New Light of Alchemy which proposed the
existence of the "food of life" within air, much later recognized as
oxygen. In 1615 Jean Beguin published the Tyrocinium Chymicum, an early chemistry
textbook, and in it draws the first-ever chemical equation. In 1637 René Descartes publishes Discours de la méthode, which contains an
outline of the scientific method.
The Dutch
chemist Jan Baptist van Helmont's work Ortus
medicinae was published posthumously in 1648; the book is cited by
some as a major transitional work between alchemy and chemistry, and as an
important influence on Robert Boyle. The book contains the results of numerous experiments and
establishes an early version of the law of conservation of
mass.
Working during the time just after Paracelsus and iatrochemistry, Jan Baptist van Helmont suggested that there are insubstantial
substances other than air and coined a name for them - "gas", from the Greek
word chaos. In addition to introducing the word "gas"
into the vocabulary of scientists, van Helmont conducted several experiments
involving gases. Jan Baptist van Helmont is also remembered today largely for
his ideas on spontaneous generation and his 5-year tree
experiment, as well as being considered the founder of pneumatic chemistry.
Anglo-Irish
chemist Robert Boyle (1627–1691) is
considered to have refined the modern scientific method for alchemy and to have
separated chemistry further from alchemy. Although his research clearly has its
roots in the alchemical tradition, Boyle is
largely regarded today as the first modern chemist, and therefore one of the
founders of modern chemistry, and one of the pioneers
of modern experimental scientific method. Although Boyle was not the original discoverer, he is best
known for Boyle's law, which he presented in 1662: the
law describes the inversely proportional relationship between the absolute pressure and volume of a gas, if the temperature is kept constant within
a closed system.
Boyle is also
credited for his landmark publication The Sceptical Chymist in 1661, which is
seen as a cornerstone book in the field of chemistry. In the work, Boyle
presents his hypothesis that every phenomenon was the result of collisions of
particles in motion. Boyle appealed to chemists to experiment and asserted that
experiments denied the limiting of chemical elements to only the classic four:
earth, fire, air, and water. He also pleaded that chemistry should cease to be
subservient to medicine or to alchemy, and
rise to the status of a science. Importantly, he advocated a rigorous approach
to scientific experiment: he believed all theories must be proved
experimentally before being regarded as true. The work contains some of the
earliest modern ideas of atoms, molecules, and chemical reaction, and marks the beginning of the history of modern chemistry.
Boyle also tried to purify chemicals to obtain reproducible
reactions. He was a vocal proponent of the mechanical philosophy proposed
by René Descartes to explain and
quantify the physical properties and interactions of material substances. Boyle
was an atomist, but favored the word corpuscle over atoms.
He commented that the finest division of matter where the properties are
retained is at the level of corpuscles. He also performed numerous
investigations with an air pump, and noted that the mercury fell as air was pumped out. He also observed that pumping
the air out of a container would extinguish a flame and kill small animals
placed inside. Boyle helped to lay the foundations for the Chemical Revolution with his mechanical corpuscular
philosophy. Boyle repeated the tree experiment of van Helmont, and was the
first to use indicators which changed colors
with acidity. Joseph Priestley, co-discoverer of the
element oxygen, which he called "dephlogisticated air".
In 1702, German chemist Georg Stahl coined the name "phlogiston" for the substance believed to be released in the process
of burning. Around 1735, Swedish chemist Georg Brandt analyzed a dark blue pigment found in copper ore. Brandt
demonstrated that the pigment contained a new element, later named cobalt. In 1751, a Swedish chemist and pupil of Stahl's named Axel Fredrik Cronstedt, identified an impurity
in copper ore as a separate metallic element, which he named nickel. Cronstedt is one of the founders of modern mineralogy. Cronstedt also discovered the mineral scheelite in
1751, which he named tungsten, meaning "heavy stone" in Swedish.
In 1754,
Scottish chemist Joseph Black isolated carbon dioxide, which he called "fixed air". In 1757, Louis Claude Cadet de
Gassicourt,
while investigating arsenic compounds, creates Cadet's fuming liquid, later discovered to
be cacodyl oxide, considered to be the
first synthetic organometallic compound. In 1758, Joseph Black formulated the
concept of latent heat to explain the thermochemistry of phase changes. In 1766, English chemist Henry Cavendish isolated hydrogen, which he called "inflammable air". Cavendish
discovered hydrogen as a colorless, odorless gas that burns and can form an
explosive mixture with air, and published a paper on the production of water by
burning inflammable air (that is, hydrogen) in dephlogisticated air (now known
to be oxygen), the latter a constituent of atmospheric air (phlogiston theory).
In 1773,
Swedish chemist Carl Wilhelm Scheele discovered oxygen, which he called "fire air", but did not immediately
publish his achievement. In 1774, English chemist Joseph Priestley independently isolated oxygen in its gaseous state,
calling it "dephlogisticated air", and published his work before
Scheele. During his lifetime, Priestley's considerable scientific
reputation rested on his invention of soda water, his writings on electricity, and his discovery of several "airs" (gases), the
most famous being what Priestley dubbed "dephlogisticated air"
(oxygen). However, Priestley's determination to defend phlogiston theory and to
reject what would become the chemical revolution eventually left him
isolated within the scientific community.
In 1781, Carl
Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from Cronstedt's scheelite (at the time named
tungsten). Scheele and Torbern Bergman suggested
that it might be possible to obtain a new metal by reducing this acid. In
1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, in
Spain, the brothers succeeded in isolating the metal now known as tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element.
Italian
physicist Alessandro Volta constructed a device
for accumulating a large charge by a series of inductions and groundings. He
investigated the 1780s discovery "animal electricity" by Luigi Galvani, and found that the electric current was generated from the contact of dissimilar metals, and
that the frog leg was only acting as a detector. Volta demonstrated in 1794
that when two metals and brine-soaked cloth or cardboard are arranged in a
circuit they produce an electric current.
In 1800, Volta
stacked several pairs of alternating copper (or silver) and zinc discs (electrodes) separated by cloth or cardboard soaked in brine (electrolyte) to increase the electrolyte conductivity.[52] When the top and bottom contacts were connected by a wire,
an electric current flowed through the
voltaic pile and the connecting wire. Thus, Volta is credited with constructing
the first electrical battery to produce electricity. Volta's method of stacking round plates of copper and zinc
separated by disks of cardboard moistened with salt solution was termed a voltaic pile.
Thus, Volta is
considered to be the founder of the discipline of electrochemistry A Galvanic cell (or voltaic cell) is an electrochemical cell that derives
electrical energy from spontaneous redox reaction taking
place within the cell. It generally consists of two different metals connected
by a salt bridge, or individual half-cells
separated by a porous membrane.
Although the archives of chemical research draw upon work from
ancient Babylonia, Egypt, and especially the Arabs and Persians after Islam, modern chemistry flourished from the time
of Antoine-Laurent de
Lavoisier,
a French chemist who is celebrated as the "father of modern chemistry". Lavoisier
demonstrated with careful measurements that transmutation of water to earth was
not possible, but that the sediment observed from boiling water came from the
container. He burnt phosphorus and sulfur in air, and proved that the products
weighed more than the original. Nevertheless, the weight gained was lost from
the air. Thus, in 1789, he established the Law of Conservation of Mass, which is also called
"Lavoisier's Law.”
The world's first ice-calorimeter, used in the winter of
1782-83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat
involved in various chemical changes;
calculations which were based on Joseph Black's prior discovery
of latent heat. These
experiments mark the foundation of thermochemistry.
Repeating the experiments of Priestley, he demonstrated that air
is composed of two parts, one of which combines with metals to form calxes.
In Considérations Générales sur la Nature des Acides (1778), he
demonstrated that the "air" responsible for combustion was also the
source of acidity. The next year, he named this portion oxygen (Greek for
acid-former), and the other azote (Greek for no life). Lavoisier thus has a
claim to the discovery of oxygen along with Priestley and Scheele. He also
discovered that the "inflammable air" discovered by Cavendish - which
he termed hydrogen (Greek for
water-former) - combined with oxygen to produce a dew, as Priestley had
reported, which appeared to be water. In Reflexions sur le Phlogistique (1783),
Lavoisier showed the phlogiston theory of combustion to be inconsistent. Mikhail Lomonosov independently established a tradition of chemistry in
Russia in the 18th century. Lomonosov also rejected the phlogiston theory, and
anticipated the kinetic theory of gases. Lomonosov
regarded heat as a form of motion, and stated the idea of conservation of
matter.
Lavoisier
worked with Claude Louis Berthollet and others to devise
a system of chemical nomenclature which serves as the
basis of the modern system of naming chemical compounds. In his Methods
of Chemical Nomenclature (1787), Lavoisier invented the system of
naming and classification still largely in use today, including names such
as sulfuric acid, sulfates, and sulfites. In 1785, Berthollet was
the first to introduce the use of chlorine gas as a commercial bleach. In the
same year he first determined the elemental composition of the gas ammonia. Berthollet first produced a modern bleaching liquid in 1789 by
passing chlorine gas through a solution of sodium carbonate - the result was a weak solution of sodium hypochlorite. Another strong chlorine
oxidant and bleach which he investigated and was the first to produce, potassium chlorate (KClO3),
is known as Berthollet's Salt. Berthollet is also known for his scientific
contributions to theory of chemical equilibria via the
mechanism of reverse chemical
reactions.
Lavoisier's Traité Élémentaire de Chimie (Elementary
Treatise of Chemistry, 1789) was the first modern chemical textbook, and
presented a unified view of new theories of chemistry, contained a clear
statement of the Law of Conservation of Mass, and denied the existence of
phlogiston. In addition, it contained a list of elements, or substances that
could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur. His list, however, also included light, and caloric, which he believed to be material substances. In the work,
Lavoisier underscored the observational basis of his chemistry, stating "I
have tried...to arrive at the truth by linking up facts; to suppress as much as
possible the use of reasoning, which is often an unreliable instrument which
deceives us, in order to follow as much as possible the torch of observation
and of experiment." Nevertheless, he believed that the real existence of
atoms was philosophically impossible. Lavoisier demonstrated that organisms
disassemble and reconstitute atmospheric air in the same manner as a burning
body.
With Pierre-Simon Laplace, Lavoisier used a calorimeter to estimate the heat evolved per unit of carbon dioxide
produced. They found the same ratio for a flame and animals, indicating that
animals produced energy by a type of combustion. Lavoisier believed in the
radical theory, believing that radicals, which function as a single group in a
chemical reaction, would combine with oxygen in reactions. He believed all
acids contained oxygen. He also discovered that diamond is a crystalline form of carbon.
While many of
Lavoisier's partners were influential for the advancement of chemistry as a
scientific discipline, his wife Marie-Anne Lavoisier was arguably the most
influential of them all. Upon their marriage, Mme. Lavoisier began to study
chemistry, English, and drawing in order to help her husband in his work either
by translating papers into English, a language which Lavoisier did not know, or
by keeping records and drawing the various apparatuses that Lavoisier used in
his labs. Through her ability to read and translate articles from Britain
for her husband, Lavoisier had access knowledge from many of the chemical
advances happening outside of his lab. Furthermore, Mme. Lavoisier kept
records of Lavoisier's work and ensured that his works were published. The
first sign of Marie-Anne's true potential as a chemist in Lavoisier's lab came
when she was translating a book by the scientist Richard Kirwan. While
translating, she stumbled upon and corrected multiple errors. When she
presented her translation, along with her notes to Lavoisier. Her edits and
contributions led to Lavoisier's refutation of the theory of phlogiston.
Lavoisier made
many fundamental contributions to the science of chemistry. Following
Lavoisier's work, chemistry acquired a strict quantitative nature, allowing
reliable predictions to be made. The revolution in chemistry which he brought
about was a result of a conscious effort to fit all experiments into the
framework of a single theory. He established the consistent use of chemical
balance, used oxygen to overthrow the phlogiston theory, and developed a new
system of chemical nomenclature. Lavoisier was beheaded during the French Revolution.
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