Introduction to chemistry
1660-The
Royal Society for improving Natural was founded in England.
1661-concept
of element – Robert Boyle. He defined acid and base.
In
1754, Scottish chemist Joseph Black isolated carbon dioxide, which he
called "fixed air".
In
1766, English chemist Henry Cavendish isolated hydrogen, which he
called "inflammable air".
In
1773, Swedish chemist Carl Wilhelm Scheele discovered oxygen, which
he called "fire air",
In
1774, English chemist Joseph Priestley independently isolated oxygen
in its gaseous state, calling it "dephlogisticated air"
1779-
oxygen theory of combustion by Lavoisier and
The
discovery of law of conservation of mass in a chemical change.
Antoine
Lavoisier revolutionized chemistry.
He named the elements carbon, hydrogen
and oxygen; discovered oxygen’s role in combustion and respiration;
established that water is a compound of hydrogen and oxygen;
discovered that sulfur is an element, and helped continue the
transformation of chemistry from a qualitative science into a
quantitative one.
Lavoisier
announced a new fundamental law of nature in 1782;
The
law of conservation of mass:
matter
is conserved in chemical reactions
1800-disovery
of Volta’s cell, a pile of dissimilar metals separated by salt
soaked card boards;
a
pile of such metals consisting of a pair of silver and zinc discs
seperated by pieces of moist cardboard.
1800-
By applying electric energy, Willium and Anthony, decomposed
water into two different gases hydrogen and oxygen. They Confirmed
that water is a compound and not an element.
The
law of constant composition
Law
of definite proportion while forming a compound-By Proust in1799;
that the elements combine in a definite ratio by mass to make new
compounds. Example; CuCO3 forms by Cu:C: O in a definite ratio, what
ever be the method of making it.
1803-Daltons’s
Atomic theory of elements and Computation of relative atomic weights
of elements.
Dalton's
fascination with gases gradually led him to formally assert that
every form of matter (whether solid, liquid or gas) was also made up
of small individual particles called Atoms.
The
main points of Dalton's atomic theory, as it eventually developed,
are:- Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.
- Atoms cannot be subdivided, created or destroyed.
- In chemical reactions, atoms are combined, separated or rearranged.
In
1808,In A
New System of Chemical Philosophy,
Dalton
introduced his belief that atoms of different elements could be
universally distinguished based on their varying atomic weights. In
so doing, he became the first scientist to explain the behavior of
atoms in terms of the measurement of weight. He also uncovered the
fact that atoms couldn't be created or destroyed.
1811-concept
of gas molecule- Avogadro. Avogadro's law that equal volumes of gases
contain equal number of particle[molecules].
1812-
Discovery of new elements by Humphrey Davy using Volta’s Battery to
decompose different salts.
Discovery
of Na, K Mg, Ca, Sr and Ba. He also discovered chlorine.
1817-
Swedish chemist, Berzelius simplified chemistry through his sugestion
that elements be represented by symbols, using the first letter of
each element’s Latin name. To indicate a proportion in a coumpound,
he wrote the appropriate number as subscript. He was especialy noted
for his determination of atomic weights and development of chemical
symbols.
Berzelius
gave the concept of catalysis for reactions which occur only in the
presence of some third substance. He also suggested the name
allotropy for the occurance of diferent forms of the same element.
In1834,
Faraday’s Electro-chemistry and the Laws of electrolysis.
Faraday
discovered that when electricity is passed through ionic solutions,
the amount of chemical change produced was proportional to the
quantity of electricity passed through it.
1840-Chemical
society was founded and Royal college of chemistry opened.
1852-concept
of valency by Edward Frankland.
1859-Bunsen
discovered that each element produces its own characteristic set of
lines in the spectrum.
1860
the first chemical congress called by Kekulay in Germany.
Following
the Karlsruhe meeting, values of relative
atomic weights,
about 1 for hydrogen, 12 for carbon, 16 for oxygen, and so forth were
adopted. This was based on a recognition that certain elements, such
as hydrogen, nitrogen, and oxygen, were composed of diatomic
molecules
and
not individual atoms.
An
important long-term result of the Karlsruhe Congress was the adoption
of the now-familiar atomic weights (actually, atomic masses) of
approximately 1 for hydrogen, 12 for carbon, 16 for oxygen, Cl 35.5,
K39, Ca 40, Br 80, Rb 85,
Sr 88, I 127, Cs 133, Ba 137
and so forth.
1869-
discovery of periodic properties of elements and periodic table of
elements.
On
March 6, 1869, Mendeleev made a formal presentation to the Russian
Chemical Society, entitled The Dependence between the Properties of
the Atomic Weights of the Elements, which described elements
according to both weight and valence.
Modern
chemistry
Discovery
of Sub-atomic particle, the electron.
In
1900 Electron was discovered as a subatomic particle.
Electron
was discovered by J. J. Thomson in Cathode Ray Tube (CRT) experiment.
- The charge of an electron was measured by R. Millikan in Oil drop experiment.
-
Bohr's
model of Hydrogen Atom:
In
1913, Neils Bohr, a student of Rutherford's, developed a new model of
the atom. He proposed that electrons are arranged in concentric
circular orbits around the nucleus. This model is patterned on the
solar system and is known as the planetary model. The Bohr model can
be summarized by the following four principles:
- Electrons occupy only certain orbits around the nucleus. Those orbits are stable and are called "stationary" orbits.
- Each orbit has an energy associated with it. The orbit nearest the nucleus has an energy of E1, the next orbit E2, etc.
- Energy is absorbed when an electron jumps from a lower orbit to a higher one and energy is emitted when an electron falls from a higher orbit to a lower orbit.
- The energy and frequency of light emitted or absorbed can be calculated by using the difference between the two orbital energies
Planck’s
Quantum theory of Black Body radiation.
Photoelectric
effect.
Theory
of relativity
The
bond theory.
Schrodinger
wave equation and electronic configuration of elements.
1928-concept
of Hybridization and multiple valency, and concept of
crystallization.
1932-Electro-negativity
figures calculated by Paulings.
1934-Artificial
Radio activity by Fermi.
1942-
Nuclear fission by Otto Hahn.
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Chemical
industry
The
scientific revolution has given birth to industrial revolution.
People
began to use science to harnace The Nature,
for profit.
1748-
Coal mining started
1760-
Iron smelting started
1765-
steam Engine.
1781-
James Watt’s Steam Engine and Industrial revolution. Steam
locomotives for transport of large loads on rail roads. By 1800, the
firm Boulton and Watts had constructed 496 steam engines.
Chamber
process for Sulfuric acid:
In
1746 John Roebuck developed the lead
chamber process
for the manufacture of sulfuric acid. Prior to this time, sulfuric
acid had been produced in glass bottles several pounds at a time. But
the lead chamber process could produce sulfuric acid by the ton.
In
the original lead chamber process, sulfur and potassium nitrate are
ignited in a room lined with lead foil. Potassium nitrate, or
saltpeter
is
an oxidizing agent oxidizes the sulfur to sulfur trioxide according
to the reaction:
6
KNO3(s) + 7 S(s) -----> 3 K2S + 6 NO(g) + 4
SO3(g)
The
floor of the room was covered with water. When the sulfur trioxide
reacted with the water, sulfuric acid was produced:
SO3(g)
+ H2O(l) -----> H2SO4(aq)
This
process was a batch process and resulted in the consumption of
potassium nitrate
1791-Leblanc
process for Soda ash:
The
Leblanc process
was an early industrial process for the production of soda ash
(sodium carbonate) used throughout the 19th century, named after its
inventor, Nicolas Leblanc. It involved two stages: production of
sodium sulfate from sodium chloride, followed by reaction of the
sodium sulfate with coal and calcium carbonate to produce sodium
carbonate.
In
1823, a factory for alkali was set up in England. By 1840 soda was
available in bulk quantity.
By
the year1870, the British-soda output reached two lakh tons annually.
The
Leblanc process was a batch process in which sodium chloride was
subjected to a series of treatments, eventually producing sodium
carbonate. In the first step, the sodium chloride was heated with
sulfuric
acid
to
produce sodium
sulfate
(called
the salt
cake)
and hydrochloric
acid gas,
according
to the chemical
equation,
in
the second step, the salt cake was mixed with crushed limestone
(calcium
carbonate)
and coal and fired. In the ensuing chemical reaction, the coal
(carbon)
was oxidized
to
carbon
dioxide,
reducing
the
sulfate
to
sulfide and leaving behind a solid mixture of sodium carbonate and
calcium sulfide, called black
ash.
Because
sodium carbonate is soluble in water, but neither calcium carbonate
nor calcium sulfide is, the soda ash was then separated from the
black ash by washing it with water. The wash water was then
evaporated to yield solid sodium carbonate. This extraction process
was termed lixiviation.
Bleaching
powder for Textile industry:
(Ca(ClO)2), calcium hydroxide (Ca(OH)2), and calcium chloride (CaCl2) in variable amounts.
St.
Rollox Chemical Works
produced almost 10,000 tons of bleaching powder in
1804,
improving exponentially its production of 52 tons in 1799. Created by
Charles Tennant (who discovered the bleaching powder), it was
considered as the first biggest chemical enterprise in the world.
Discovery
of coal and distillation to make coke
Destructive
distillation of coal:
when
coal is destructively distilled, coal gas, ammonia, coal tar and coke
were obtained.
When
coal-tar was fractionally distilled, light oil, middle oil, heavy oil
were obtained.
Abraham
Pineo Gesner,
a Canadian geologist developed a process to refine a liquid fuel from
coal, bitumen and oil shale. His new discovery, which he named
kerosene, burned more cleanly and was less expensive than competing
products, such as whale oil. In 1850, Gesner created the Kerosene
Gaslight Company and began installing lighting in the streets in
Halifax and other cities.
1828-Blast
Furnace for pig-Iron extraction from iron-ore, using coke and hot air
pumping[Hot blast process].
Discovery
of crude oil and distillation to make kerosene to light the streets.
The
first oil well is drilled successfully near Titusville, Pennsylvania
in 1859. This oil well of 70 feet marked the beginning of the
Petroleum Industry.
BejamÃn
Silliman, from New Haven, Conneticut, obtained valuable products from
the destillation of petroleum in 1855. Between these valuable
products were the naphthalene, gasoline, tar and other solvents.
Industrial
organic chemistry and plastic materials.
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