Definition Of Chemistry
Chemistry is the science of molecules and their transformations. It is the science not so much of the one hundred elements but of the infinite variety of molecules that may be built from them-ROALD HOFFMANN
Other Definitions Of Chemistry
- The branch of science that studies the preparation, properties, structure, and reactions of material substances.
- Chemistry is the branch of science which deals with the composition of matter and also the physical and chemical characteristics associated with different material objects.
- Chemistry is the branch of science that involved with elements and compounds composed of atoms, molecules and ions; their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.
- Chemistry is the study of matter, its properties, how and why substances combine and separate to form other substances. ‘Matter’ defined as anything that has mass and occupied a space. This seeks to understand not only the properties of matter like mass or composition of a chemical element but also how and why matter undergoes certain changes.
History Of Chemistry
The history of Chemistry spans a period from very old times to the present. Since several millennia BC, civilizations were using technologies that would eventually from the basis of the various branches of the chemistry. Examples include extracting metals from ores, making alloys from bronze, making pottery from glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat into soap, and making glass. Chemistry was preceded by its protoscience, alchemy, which is an intutive but non-scientific approach to understand the constituents of matter and their interactions. It was unsuccessful in explaining the nature of matter and its transformations, but by performing experiments and recording the results, alchemists set the stage of modern chemistry.
Chemistry as a body of knowledge distinct from alchemy began to emerge when a clear differentiation was made between them by Robert Boyle in his work The Sceptical Chymist (1661). While both aichemy and chemistry are concerned with matter and its transformations, the crucial difference was given by the scientific method that chemists employed in their work. Chemistry is considered to have become an established science with the work of ANTOINE LAVOISIER, who developed a law of conservation of mass that demaned careful measurement and quantitative observations of chemical phenomena.
ANTOINE LAVOISIER considered the “Father of Chemistry”.
Development Of Chemistry
Chemistry, as we understand it today, is not very old discipline. Chemistry was not studied for its own sake, rather it came up as a result of search for two interesting things :
- Philosopher’s stone (Paras) which would convert all baser metals e.g. iron and copper into gold.
- ‘Elexir of Life’ which would grant immortality.
People in ancient India, already had the knowledge of many scientific phenomenon much before the advent of modern science. They applied that knowledge in various walks of life. Chemistry developed mainly in the form of Alchemy and Iatrochemistry during 1300-1600 CE. Modern chemistry took shape in the 18th century Europe, after a few centuries of alchemical traditions which were introduced in Europe by the Arabs.
Other cultures- especially the Chinese and the Indian- had their own alchemical traditions. These included much knowledge of chemical processes and techniques.
In ancient India, chemistry was called Rasayan Shastra, Rastantra, Ras Kriya or Rasvidya. It included metallurgy, medicine, manufacture of cosmetics, glass, dyes, etc. Systematic excavations at Mohenjodaro in Sindh and Harappa in Punjab to prove that the story of development of chemistry in India is very old. Archaeological findings show that baked bricks were used in construction work. It shows the mass production of pottery, which can be regarded as the earliest chemical processes, in which materials were mixed, moulded and subjected to heat byusing fire to achieve desirable qualities. Remains of glazed pottery have been found in Mohenjodaro. Gypsum cement has been used in the construction work. It contains lime, sand and traces of CaCO3. Harappans made faience, a sort of glass which was used in ornaments.
They melted and forged a variety of objects from metals, such as lead, silver, gold, and copper. They improved the hardness of copper for making artefacts by using tin and arsenic. A number of glass objects were found in Maski in South India (1000-900BCE), and Hastinapur and Taxila in North India (1000-200BCE). Glass and glazes were coloured by addition of colouring agents like metal oxides. Copper metallurgy in India dates back to the beginning of chalcolithic cultures in the subcontinent. There are much archaeological evidences to support the view that technologies for extraction of copper and iron were developed
According to Rigveda, tanning of leather and dying of cotton were practised during 1000-400 BCE. The golden gloss of the black polished ware of northern India could not be replicated and is still a chemical mystery. These wares indicate the mastery with which kiln temperatures could be controlled. Kautilya’s Arthashastra describes the production of salt from sea.
A vast number of statements and materials described in the ancient Vedic literature can be shown to agree with modern scientific findings. Copper utensils, iron, gold, silver ornaments and terracotta discs and painted grey pottery have been found in many archaeological sites in North India. Sushruta Samhita explains the importance of alkalies. The Charaka Samhita mentions ancient indians who knew how to prepare sulphuric acid, nitric acid and oxides of copper, tin and zinc; the sulphates of copper, zinc and iron and the carbonates of lead and iron.
Rasopanishada describes the preparation of gunpowder mixture. Tamil texts also describe the preparation of fireworks using Sulphur, charcoal, saltpetre (i.e. potassium nitrate), mercury, champhor, etc.
Nagarjuna was a great Indian scientist. He was a reputed chemist, an alchemist and a metallurgist. His work Rasratnakar deals with the formulation of mercury compounds. He has also discussed methods for the extraction of metals, like gold, silver, tin and copper. Abook, Rsarnavam, appeared around 800 CE. It discusses the uses of various furnaces, ovens and crucibles for different purposes. It describes methods by which metals could be identified by flame colour.
Chakrapani discovered mercury sulphide. The credit for inventing soap also goes to him. He used mustard oil and some alkalies as ingredients for making soap. Indian began making soaps in the 18th century CE. Oil of Eranda and seeds of Mahua plant and calcium carbonate were used for making soap.
The paintings found on the walls of Ajanta and Ellora, which look fresh even after ages, testify to a high level of science achieved in ancient India. Varahmihir’s Brihat Samhitta is a sort of encyclopaedia, which was composed in the sixth century CE. It informs about the preparation of glutinous material to be applied on the walls and roofs of houses and temples. It was prepared entirely from extracts of various plants, fruits, seeds and barks, which were concentrate d by boiling, and then, treated with various resins. It will be intresting to test such materials scientifically and assess them for use.
A number of classical texts, like Atharvaveda (1000BCE) mention some dye stuff, the material used were turmeric, madder, sunflower, orpiment, cochineal and lac. Some other substances having tinting property were kamplcica, pattanga and jatuka.
Varahmihir’s Brihat Samhita gives references to perfume and cosmetics. Recipes for hair dying were made from plants, like indigo and minerals like iron powder, black iron or steel and acidic extracts of sour rice gruel. Gandhayukli describes recipes for making scents, mouth perfumes, bath powders, incense and talcum powder.
Paper was known to India in the 17th century as account of Chinese traveller I-tsing describes. Excavations at Taxila indicate that ink was used in India from fourth century. Colours of ink were made from chalk, red lead and minimum.
It seems that the process of fermentation as well known to Indians. Vedas and Kautilya’s Arthashastra mention about many types of liquors. Charaka Samhito also mentions ingredients, such as barks of plants, stem, flowers, leaves, woods, cereals, fruits and sugarcane for making Asavas.
The concept that matter is ultimately made of indivisible building blocks, appeared in India a few centuries BCE as a part of philosophical speculations. Acharya Kanda, born in 600 BCE, originally known by the name Kashyap, was the first proponent of the ‘atomic theory’. He formulated the theory of very small indivisible particles, which he named ‘Paramanu’ (comparable to atoms). He authored the text Vaiseshika Sutras.
According to him, all substances are aggregated form of smaller units called atoms (paramanu), which are eternal, indestructible, spherical, suprasensible and in motion in the original state. He explained that this individual entity cannot be sensed through any human organ. Kanda added that there are varieties of atoms that are as different as the different classes of substances. He said these(paramanu) could form pairs or triplets, among other combinations and unseen forces cause interaction between them. He conceptualised this theory around 2500 years before John Dalton (1766-1844).
Charaka Samhita is the oldest Ayurvedic epic of India Charaka Samhita. Extreme reduction of particle size is termed as nanotechnology. Charaka Samhita describes the use of bhasma of metals in the treatment of ailments. Now-a-days, it has been proved that bhasmas have nanoparticles of metals.
After the decline of alchemy, Iatrochemistry reached a steady state, but it too declined due to introduction and practise of western medicinal system in the 20th century.
During this period of stagnation, pharmaceutical industry based on Ayurveda continued to exist, but it too declined gradually. It took about 100-150 years for Indians to learn and adopt new techniques. During this time, foreign products poured in. As a result, indigenous traditional techniques gradually declined. Modern science appeared in Indian scene In the later part of nineteenth century. By the mid-nineteenth century, European scientists started coming to India and modern chemistry starts growing.
Branches Of Chemistry
Traditionally, chemistry has been broken into five main subdisciplines: Organic, Inorganic,
Physical, Analytical and Biochemistry.
Organic chemistry studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. The study of structures determines their chemical composition and formula and the study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behaviour. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and the study of individual organic molecules in the laboratory and via theoretical study.
Organic chemistry is the chemistry of carbon compounds and all organic compounds contain carbon however, not all compounds that contains carbon are organic compounds. There are some compounds of carbon that are not classified as organic such as carbonate minerals(e.g., sodium carbonate, Na CO3, and calcium carbonate, Ca CO3) and cyanide compounds ( such as potassium cyanide, KCN, or any of the metallic cyanide derivative) which are designated as inorganic compounds.
Therefore, a more useful and less confusing description of organic chemistry might be that chemistry of compounds of carbon that usually contains hydrogen as well as carbonaceous compounds that, in addition to carbon and hydrogen, may also contain other elements such as oxygen, nitrogen, sulphur, phosphorus, or any of the halogens as well as a host of other carbonaceous derivatives. On a majority of the carbon-containing compounds are organic compounds and organic chemistry is the chemistry of these compounds.
Understnding organic chemistry involves being capable not only of explaining and sometimes predicting important features of organic chemical reactions, but also designing novel reactions or sequences of reactions for producing particular organic molecules. Developing such an understanding these days, will almost certainly involve the study of mechanisms of many different organic reactions. Clearly, mechanisms have and important place in organic chemistry.
Organic chemistry is an important and dynamic field, where the number of identified organic compound are immense and increased each day. Naming of these organic chemical compounds are made according to the rules defined in IUPAC.
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Inorganic chemistry studies the chemical compounds in inorganic or non-living things such as minerals and metals and covers all the chemical compounds except the carbon-based compounds. It concerned with the properties and behavior of inorganic compounds, which include metals, minerals, and organometallic compounds. The word organic refers to the compounds which contain the carbon atoms in it. So the branch of chemistry that deals with the study of compounds, which does not consist of carbon-hydrogen atoms in it, is called ‘Inorganic Chemistry’. In simple words, it is opposite to that of Organic Chemistry.
But this definition is not completely accurate. According to ‘American Chemically Society’ some compounds studied in inorganic chemistry like organometallic compounds contain metals which are metals that are attached to carbon, the main element that’s studied in organic chemistry.
Inorganic Chemistry has application in every aspect of the chemical industry including catalysis material science, pigments, surfactants, coating, medication, fuels and agriculture. In some ways, the field of medicinal inorganic chemistry originated with the Ancients, who turned to the mystical appeal of gold and copper for healing powers. In the modern Era, the world’s first blockbuster drug was the arsenic-containing anti-syphilis agent salvarsan.
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Physical chemistry is the study of how matter behaves on a molecular and atomic level and how chemical reaction occur. Based on their analysis, physical chemists may develop new theories, such as how complex structures are formed. Physical chemists often work with materials scientists to research and develop potential uses for new materials. Unlike other branches, it deals with the principles of physics underlying all chemical interactions, seeking to measure, correlate, and explain the quantitative aspects of reactions.
For example-: Figuring out how atom move and interact with each other or why some liquid including water turn into vapour at high temperature. Physical chemists try to understand these phenomena at very small scale. On the level of atoms and molecules to derive about how chemical reaction work and what gives specific material their own unique properties.
Physical chemistry is the examination of how matter carries on a sub-nuclear and atomic level and how creation reactions happen. Considering their examinations physical researcher may develop new theories, for instance , how complex structures are formed. Physical investigative specialists frequently work personally with materials analysts to ask about and make potential uses for new materials.
Physical chemistry applies the method of thermodynamics, biophysics. Their application covers core aspects of biophysical chemistry, while showing how biochemists and biophysicts use principle of physical chemistry to solve real problems in biological systems.
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Analytical chemistry is the science of obtaining, processing, and communicating information about the composition and structure of matter. In other words, it is the art and science of determing what matter is and how much of it exists. In 2012, analytical chemistry was the most popular field of work for ACS chemists.
Analytical chemists use their knowledge of chemistry, instrumentation, computers and statistics to solve problems in almost all kinds of industries.
For example-: their measurements are used to assure the safety and quality of food, pharmaceutical and water to assure compliance with environmental and their regulations to support to support the legal processes, to help physicians diagnose disease, and to provide measurement and documentation essential to trade and commerce.
Analytical chemistry has applications including in forensic science, bioanalysis, clinical analysis, environmental analysis and material analysis.
Analytical chemistry plays an enormous role in our society, such as in drug manufacturing, process control in industry, environmental monitoring, medicinal diagnostics, food production, and forensic surveys. It is also of great importance in different research areas.
Read Full Article On Analytical Chemistry- What is Analytical Chemistry | Definition, Branches, Applications, Examples
Biochemistry is the branch of science that explores the chemical processes within and related to living organisms. It is a laboratory based science that brings together biology and chemistry. By using chemical knowledge and techniques, biochemists can understand and solve biological problems.
Biochemistry focuses on processes happening at a molecular level. It focuses on what’s happening inside our cells, studying components like proteins, lipids and organelles. It also looks at how cells communicate with each other, for example during growth or fighting illness. Biochemists need to understand how the structure of a molecule relates to its function, allowing them to predict how molecules will interact.
Biochemistry covers a range of scientific disciplines, including genetics, microbiology, forensics, plant science and medicine. Because of its breadth, biochemistry is very important and advances in this field of science over the past 100 years have been staggering. It’s a very exciting time to be part of this fascinating area of study.
Biochemistry is the study of the chemical substances and processes that occur in plants, animals, and microorganisms and of the changes they undergo during development and life. It deals with the chemistry of life, and as such it draws on the techniques of analytical, organic, and physical chemistry, as well as those of physiologists concerned with the molecular basis of vital processes. All chemical changes within the organism—either the degradation of substances, generally to gain necessary energy, or the buildup of complex molecules necessary for life processes—are collectively called metabolism. These chemical changes depend on the action of organic catalysts known as enzymes, and enzymes, in turn, depend for their existence
on the genetic apparatus of the cell.
It is not surprising, therefore, that biochemistry enters into the investigation of chemical changes in disease, drug action, and other aspects of medicine, as well as in nutrition, genetics, and agriculture. The term biochemistry is synonymous with two somewhat older terms: physiological chemistry and biological chemistry. Those aspects of biochemistry that deal with the chemistry and function of very large molecules (e.g., proteins and nucleic acids) are often grouped under the term molecular biology.
The findings of biochemistry are applied primarily in medicine, nutrition and agriculture. In medicine, biochemists investigate the causes and cures of diseases. Nutrition studies how to maintain health and wellness and also the effects of nutritional deficiencies.
Scope In Chemistry
Studying chemistry is lucrative from many perspectives and there are numerous benefits of studying it. Being a central science, Chemistry is used in every aspect of a person’s life from the food consumed to the products used. The improvement of chemical science has altered the premise of current medication. With ever-increasing research in chemistry, marvel drugs like penicillin and streptomycin have been developed. Enlisted below are the manifold reason for pursuing a degree in chemistry and establishing a career in the field of chemical science.
- It teaches useful skills that can be used in practical life when dealing with chemicals.
- With more number of students pursuing chemistry, there has been unprecednted progress in the production of new medicines for treating fatal diseases.
- A student gets acquainted with the various chemicals present in the environment and thus has a better understanding of how natural processes occur.
- A command over chemistry helps in distinguishing between chemicals and using them for the appropriate reason.
- Chemistry is a popular course and there exists a large number of professions that a person with a degree in chemistry can work in.
Studying in chemistry opens up a world of possibilities. There is an array of jobs in the field of chemistry. The job profiles can be found across different areas and thus there are a large number of occupations that one can seek in the wake of finishing a course in chemistry. Mentioned below are some of the important profiles one can work in after getting a degree in the field of chemistry.
Importance Of Chemistry
The present era is known as scientific era. There is a competition and a race going on among the scientists in different countries to explore more and more avenues for the betterment of mankind. Chemistry has direct impact on our life and has wide range of applications in different fields. A few important out of these are discussed :
In Agriculture and Food-:
We all know that over the years, the population is increasing at an alarming rate particularly in developing countries like India. It is, indeed a problem to feed the masses. Chemists have to come to the rescue. A variety of new fertilizers have been developed. The well known among them like urea, ammonium nitrate, ammonium sulphate, calcium super phosphate, etc. have been prepared by chemists only. Similarly, a large number of pesticides, fungicides and insecticides have been developed. This has definitely increased the cost of different food items but there is no dearth of them. It is for the government to have a check or control over the price of essential food materials like wheat, rice etc.
The most important contribution by chemists is in the field of health and sanitation. People used to die in lakhs every year because of epidemics like cholera, plague, malaria etc. These are now the things of the past. The broad spectrum antibiotics like chloramphenicol, streptomycin, amplicillin etc. are effective against variety of bacterias that cause diseases. Small pox has been completed eradicated. War has been launched to check polio. The vaccines are given free of cost many times during the year. The drugs cisplatin, taxol etc. which are very effective in curing deadly disease like cancer, are chemical compounds. A recently prepared chemical compound Azidothymidine (AZT) is helping the patients suffering from AIDS. It is only because of the sustained efforts and researches carried by chemists that the overall life span has increases. This is probably one of the reasons for the population increase.
The impact of chemistry in the industrial growth is remarkable. Synthetic polymers like polythene, terylene, bakelite, nylon-66, nylon-6 and many more have brought a revolution. Beautiful carpets, floor tiles, variety of paints have made our life glamorous. Synthetic rubber has completely replaced natural rubber. Similarly, terycot, terywool, terysilk etc. have taken the place of cotton, wool and silk. The major contribution in this field is by organic chemists. We are highly indebted to them for their remarkable efforts.
In Checking Pollution-:
The rapid industrialization all over the world has resulted in lot of pollution . Poisonous gases and chemicals are being constantly released in atmosphere. They are polluting environment at an alarming rate. For example, refrigerants like chlorofluorocarbons (CFCs) have depleted ozone cover and exposed all living beings to the extremely harmful ultraviolet radiations. Chemists have accepted this is as challenge . They are working day and night to develop substitutes which may cause lesser pollution. For example, CNG (compressed natural gas), a substitute of petrol is very effective in checking pollution caused by automobiles. Similarly, biodegradable polymers are being synthesized to replace non-biodegradable polymers like plastics. This field is still wide open. The society as a whole is looking to the scientists, particularly the chemists to lesson the miseries.
Chemistry In Our Daily Lives
Might think of chemistry only in the context of lab tests, food additives or dangerous substances but the field of chemistry involves everything us. Everything you see, smell, taste and touch involves chemistry and chemicals (matter).
According to the ‘American Chemical Society’ hearing, seeing, tasting and touching all involves intricate series of chemical reactions in our body. So if u don’t work as a chemist you are doing chemistry or something that involves chemistry.
In everyday’s life, you do chemistry when you cook, when you cleaning detergents to wipe off your counter, when you take medicine or when you dilute concentrated juice so that the taste isn’t intense. These chemicals and chemical processes studied by biochemists are not considered ‘living’ but understanding them is important to understanding how life works.
Examples of Chemistry in our daily lives
- Human body facilitates thousand of chemical reaction every day from digestion of food to the movement of the muscles.
- The process of photosynthesis that enables plant to convert water, sunlight and carbon dioxide into glucose and oxygen is chemical reaction. This process Is the foundation upon which the entire food chain built.
- Soaps and detergents that are used for hygine work using a chemical processes called Emulsification. Furthermore they are produced using a chemical process called Saponification.
- The sunscreen used by humans to protect themselves from the harmful uv radiation of the sun is based on chemistry. These lotions and creams consist of a combination of inorganic and organic compounds that either filter or block the uv radiations.
- Whenever we are feeling happy, sad, relaxed or stressed, there are many chemical reactions taking place in our body. It is because of the chemical messengers called neurotransmitters released in the brain that we can fall in love and cry rivers because of heartbreak.
- We all know our body is about 60%, but then what composes the rest of it? Carbon, Hydrogen, Nitrogen and Oxygen. These elements compose 96% of the human body. Whereas the rest 4% is composed of about 60 elements. Some of these elements include calcium, phosphorus, potassium, and sulphur.
- Digestion relies on chemical reactions between food and acids and enzymes to break down molecules into nutrients the body can absorb and use.
- Drugs work because of chemistry. The chemical compounds may fit into the binding site for natural chemicals in our body (e.g., block pain receptors) or may attack chemicals found in pathogens, but not human cells (e.g., antibiotics).
- Cooking is a chemical change that alters food to make it more palatable, kill dangerous microorganisms, and make it more digestible. The heat of cooking may denature proteins, promote chemical reactions between ingredients, carmelize sugars, etc.
- Medicines are the best examples of chemistry which save us from diseases and make us able to live. They contain the chemical compounds.