Dr. Pushpanjali Singh (Home)

Chemistry – A Perspective

Chemistry is not an isolated discipline, for it merges into physics and biology. The origin of the term is obscure. Chemistry evolved from the medieval practice of alchemy. It's bases were laid by such men as Boyle, Lavoisier, Priestly, Berzelius, Avogadro, Dalton and Pasteur.The traditional definition goes something like this: “Chemistry is the study of the nature, properties, and composition of matter, and how these undergo changes”. But as per me, chemistry says.

C- curiousity; H- helps;      E- established; M- Methods; I-investigation; S- substances; T- Triggers; R-revolution; Y- Youth

So we can define“ Chemistry is branch of science which starts with curiosity that helps to established several method of investigation of substances(matter) , which triggers revolution for youth”.

Chemistry, for instance, now overlaps so much with geology (thus we have geochemistry), astronomy (astrochemistry), and physics (physical and analytical chemistry) that it is probably impossible to devise a really good modern definition of chemistry, except, perhaps, to fall back on the operational definition: Chemistry is what chemists do!

Chemistry is a way of studying matter. What is matter? As is true with many of those words which are really basic to science, matter is hard to define. It is often said that matter is anything which has mass and occupies space. But then what are "mass" and "space"? Although we can define these, the process yields very little insight into what matter is. So let us just say that matter is anything which has real physical existence; in a word matter is just stuff. Iron, air, wool, gold, milk, aspirin, monkeys, rubber, and pizza - these are all matter. Some things which are not matter are heat, cold, colours, dreams hopes, ideas, sunlight, beauty, fear, and x-rays. None of these is "stuff"; none is matter.

A sample of matter can be either a pure substance or a mixture. A pure substance may be a single element, such as copper or oxygen, or a compound of two or more elements in a fixed ratio, such as salt (39.34 % sodium and 60.66 % chlorine) or table sugar (42.11 % carbon, 6.48 % hydrogen, and 51.41 % oxygen).

A mixture is a collection of pure substances simply mixed together. Its composition is variable, as are its properties. Examples of mixtures are milk, wood, concrete, saltwater, air, granite, motor oil, chocolate, and elephants.

A pure substance can be a solid, a liquid, or a gas; these are the three states of matter A solid maintains its volume and shape; a liquid, its volume only; and a gas, neither volume nor shape.

One of the goals of chemistry is to be able to describe the properties of matter in terms of its internal structure, the arrangement and interrelationship of its parts. This word, structure, sometimes refers to the physical arrangement of particles, such as atoms or molecules in space. At other times it is used to indicate some other arrangement, such as the arrangement of energy levels of an electron in an atom. The structure of matter determines its properties. Properties can be classed as either physical or chemical. A physical property of a substance can be characterized without specific reference to any other substance and usually describes the response of the substance to some external influence, such as heat, light, force, electricity, etc. Physical properties include boiling point, melting point, thermal (heat) conductivity, colour, refractive index, viscosity, reflectivity, hardness, tensile strength, and electrical conductivity.

History

“Chemistry as a science was almost created by the Muslims; for in this field, where the Greeks (so far as we know) were confined to industrial experience and vague hypothesis, the Saracens introduced precise observation, controlled experiment, and careful records. Alchemy, which the Muslims inherited from Egypt, contributed to chemistry by a thousand incidental discoveries, and by its method, which was the most scientific of all medieval operations”.

The emergence of chemistry in Europe was primarily due to the recurrent incidence of the plague and blights there during the so called Dark Ages This gave rise to a need for medicines. It was thought that there exists a universal medicine called the Elixir of Life that can cure all diseases.

Chemistry indeed came of age when Antoine Lavoisier (1743–1794), developed the theory of Conservation of mass in 1783; and the development of the Atomic Theory by John Dalton around 1800. The Law of Conservation of Mass resulted in the reformulation of chemistry based on this lawand the oxygen theory of combustion, which was largely based on the work of Lavoisier. Lavoisier's fundamental contributions to chemistry were a result of a conscious effort to fit all experiments into the framework of a single theory.

Lavoisier also worked to translate the archaic and technical language of chemistry into something that could be easily understood by the largely uneducated masses, leading to an increased public interest in chemistry. All these advances in chemistry led to what is usually called the chemical revolution. The contributions of Lavoisier led to what is now called modern chemistry—the chemistry that is studied in educational institutions all over the world. It is because of these and other contributions that Antoine Lavoisier is often celebrated as the "Father of Modern Chemistry”.

The basic concept which are the building blocks of chemistry  are –

Atom

An atom is the basic unit of chemistry. It consists of a positively charged core (the atomic nucleus) which contains protons and neutrons, and which maintains a number of electrons to balance the positive charge in the nucleus. The atom is the smallest entity that can have the chemical properties of the element, such as electronegativity, ionization potential,  oxidation state etc.

Element

The concept of chemical element is related to that of chemical substance. A chemical element is specifically a substance which is composed of a single type of atom. A chemical element is characterized by a particular number of protons in the nuclei of its atoms. This number is known as the atomic number of the element.

Compound

A compound is a substance with a particular ratio of atoms of particular chemical elements which determines its composition, and a particular organization which determines chemical properties. For example, water is a compound containing hydrogen and oxygen in the ratio of two to one, with the oxygen atom between the two hydrogen atoms, and an angle of 104.5° between them. Compounds are formed and interconverted by chemical reactions.

Molecule

A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, its potential to undergo a certain set of chemical reactions with other substances.

References

Simpson, David (29 June 2005). "Lucretius (c. 99 - c. 55 BCE)". The Internet History of Philosophy. http://www.iep.utm.edu/l/lucretiu.htm. Retrieved 2007-01-09.

a b Richard Myers (2003). "The Basics of Chemistry". Greenwood Publishing Group. pp.13–14. ISBN 0-313-31664-3

Morris Kline (1985) Mathematics for the nonmathematician. Courier Dover Publications. p. 284. ISBN 0-486-24823-2

a b Will Durant (1980), The Age of Faith (The Story of Civilization, Volume 4), p. 162-186, Simon & Schuster, ISBN 0-671-01200-2

Dr. K. Ajram (1992), Miracle of Islamic Science, Appendix B, Knowledge House Publishers, ISBN 0-911119-43-4