What is Chemistry ?

1. CHEMISTRY
S PRABHANJAN KUMAR
#Pharm D

2. What is Chemistry ?
• The branch of science concerned with the
substances of which matter is composed, the
investigation of their properties and reactions,
and the use of such reactions to form new
substances. (or)
• Chemistry is the study of matter, its properties,
how and why substances combine or separate to
form other substances, and how substances
interact with energy.

3. The history of chemistry represents a time span from
ancient history to the present. By 1000 BC, civilizations
used technologies that would eventually form the basis
of the various branches of chemistry. ... However, by
performing experiments and recording the results,
alchemists set the stage for modern chemistry.
History :

4. In the eighth century A.D., Jābir ibn Hayyān, a Muslim
astronomer, philosopher and scientist, became one of
the first to use scientific methods to study materials.
Also known by his Latinized name, Geber
Robert Boyle(1627-1691) studied the behavior of gases
and discovered the inverse relationship between volume
and pressure of a gas. He also stated that “all reality and
change can be described in terms of elementary particles
and their motion

5. By the 1700s, the Age of
Enlightenment had taken
root all over Europe.
Joseph Priestley (1733-
1804) disproved the idea
that air was an indivisible
element. He showed that
it was, instead, a
combination of gases
when he isolated oxygen
and went on to discover
seven other discreet gases
In 1794, Joseph Proust
studied pure chemical
compounds and stated the
Law of Definite Proportions
— a chemical compound
will always have its own
characteristic ratio of
elemental components.
Water, for instance, always
has a two-to-one ratio of
hydrogen to oxygen.

6. Antoine Lavoisier (1743-1794) was a French chemist who
made important contributions to the science. While
working as a tax collector, Lavoisier helped to develop the
metric system in order to insure uniform weights and
measures.
Amedeo Avogadro (1776-1856) was an Italian lawyer
who began to study science and mathematics in 1800.
Expanding on the work of Boyle and Charles, he clarified
the difference between atoms and molecules

7. In 1803, an English meteorologist began to speculate on the
phenomenon of water vapor. John Dalton (1766-1844) was
aware that water vapor is part of the atmosphere, but
experiments showed that water vapor would not form in
certain other gases.
Dmitri Mendeleev (1834-1907) was a Russian chemist
known for developing the first Periodic Table of the
Elements. He listed the 63 known elements and their
properties on cards. When he arranged the elements in
order of increasing atomic mass, he could group elements
with similar properties

9. In 1896, Henri Becquerel discovered radiation. Along with
Pierre and Marie Curie, he showed that certain elements
emit energy at fixed rates. In 1903, Becquerel shared a
Nobel Prize with the Curies for the discovery of
radioactivity.
In 1900, Max Planck discovered that energy must be
emitted in discreet units that he called “quanta” (since
named photons)

10. In 1911, Ernst Rutherford demonstrated that atoms
consisted of a tiny dense positively charged region
surrounded by relatively large areas of empty space in
which still smaller, negatively charged particles (electrons)
move. Rutherford assumed that the electrons orbit the
nucleus in separate neat orbits, just as the planets orbit the
sun.
he could not explain why the electrons were not simply
pulled into the nucleus thus destroying the atom.

11. Niels Bohr’s (1885-1962) atomic model solved this problem
by using Planck’s information. Photons are emitted from an
electrically stimulated atom only at certain frequencies. He
hypothesized that electrons inhabit distinct energy levels
and light is only emitted when an electrically “excited”
electron is forced to change energy levels.

12. In 1935, James Chadwick was awarded the Nobel Prize for
his discovery that there are an equal number of
electrically neutral particles in the nucleus of an atom.
Since neutrons are electrically neutral, they are not
deflected by either electrons or protons.

13. Concepts are essential for the study of chemistry
1.MATTER
2.ATOM
3.ELEMENT
4.COMPOUND
5.MOLECULE
6.PHASE
7.BONDING
8.ENERGY
9.REACTION
10.IONS & SALTS
11.ACIDITY & BASICITY
12.REDOX
13.EQUILIBRIUM
14.CHEMICAL LAWS

14. Types Of Chemistry / Main Branchs :
Organic Chemistry
Analytical Chemistry
Physical Chemistry
Inorganic Chemistry
Biochemistry Chemistry

15. Organic Chemistry :
Organic chemistry is the study of the structure, properties,
composition, reactions, and preparation of carbon-
containing compounds, which include not only
hydrocarbons but also compounds with any number of
other elements, including hydrogen (most compounds
contain at least one carbon–hydrogen bond), nitrogen,
oxygen, ...

16. Analytical Chemistry :
Analytical chemistry studies and uses instruments and
methods used to separate, identify, and quantify matter.
In practice, separation, identification or quantification
may constitute the entire analysis or be combined with
another method. Separation isolates analytes.

17. Physical Chemistry :
Physical chemistry is the study of macroscopic, atomic,
subatomic, and particulate phenomena in chemical
systems in terms of the principles, practices, and concepts
of physics such as motion, energy, force, time,
thermodynamics, quantum chemistry, statistical
mechanics, analytical dynamics and chemical equilibrium

18. In Organic Chemistry :
Inorganic chemistry deals with the synthesis and
behavior of inorganic and organometallic compounds.
This field covers all chemical compounds except the
myriad organic compounds

19. Bio Chemistry :
Biochemistry, sometimes called biological chemistry, is
the study of chemical processes within and relating to
living organisms. Biochemical processes give rise to the
complexity of life.

20. An experiment is a question which science poses
to Nature, and a measurement is the recording
of Nature's answer.
- Max Planck