Chemistry

Chemistry is a physical science. It is the science of matter and the changes it undergoes. It studies various atoms, molecules, crystals and other aggregates of matter whether in isolation or combination and incorporates the concepts of energy and entropy in relation to the spontaneity of chemical processes. The science of matter is also addressed by physics, but while physics takes a more general and fundamental approach, chemistry is more specialized, being concerned with the composition, behavior, structure, and properties of matter, as well as the changes it undergoes during chemical reactions. Matter is made up of either pure substances or mixtures of pure substances. The change from one substance into another is what chemists call a chemical change, or chemical reaction, and it’s a big deal because when it occurs, a brand-new substance is created. Chemistry is sometimes called "the central science" because it connects physics with other natural sciences such as geology and biology. Chemistry is a branch of physical science but distinct from physics. Our entire universe is made up of matter which is constantly changing forms and evolving into other forms of energy. Chemistry is defined as the study or science of this ever changing matter. Or chemistry is essentially the study of materials and the development of new materials for the betterment of humanity.

Origin/History

The root of the knowledge of chemistry can be traced back to as early as 3500 B.C in Egypt and Mesopotamia. Practical implementation of chemistry was mainly found in the form of crafts like metallurgy, pottery, and dyes without any idea of the chemical principles involved in it. The basic ideas of element and compound were first formulated by the Greek philosophers during the period from 500 to 300 B.C. Opinion varied, but it was generally believed that four elements (fire, air, water, and earth) combined to form all things. Aristotle's definition of a simple body as "one into which other bodies can be decomposed and which itself is not capable of being divided" is close to the modern definition of element.The beginnings of chemistry, or alchemy, as it was first known, are mingled with occultism and magic. Interests of the period were the transmutation of base metals into gold, the imitation of precious gems, and the search for the elixir of life, thought to grant immortality. Muslim conquests in the 7th century A.D. diffused the remains of Hellenistic civilization to the Arab world. The first chemical treatises to become well known in Europe were Latin translations of Arabic works, made in Spain A.D. 1144. It was the  Latin translation of Jābir’s Kitab al-Kimya. Hence it is often erroneously supposed that chemistry originated among the Arabs. Alchemy developed extensively during the Middle Ages, cultivated largely by itinerant scholars who wandered over Europe looking for patrons.

Evolution of Modern Chemistry

Boyle is considered as the father of modern chemistry. However, another scientist Antoine Lavoisier is also equivalent to Boyle.  Boyle first invented the very foundation of Gas Laws. He did experiments using an air pump under reduced pressure and discovered that volume and pressure are inversely related in gases. another scientist Hooke gave the first  explanation of combustion-as combination with air-while Mayow studied animal respiration. Even as the English chemists were moving toward the correct theory of combustion, two Germans, J. J. Becher and G. E. Stahl, introduced the false phlogiston theory of combustion, which held that the substance phlogiston is contained in all combustible bodies and escapes when the bodies burn.

The discovery of various gases and experimentations on air was crucial in the historical development of chemistry.  Carbon dioxide was originally known as fixed air untill it was rediscovered by Joseph Black in 1754. Hydrogen was discovered by Boyle. It was  later carefully studied by Henry Cavendish. Hydrogen was initially called inflammable air and was sometimes identified with phlogiston itself. Cavendish also showed that the explosion of hydrogen and oxygen produces water. C. W. Scheele found that air is composed of two fluids, only one of which supports combustion. He was the first to obtain pure oxygen (1771-73), although he did not recognize it as an element. Joseph Priestley independently discovered oxygen by heating the red oxide of mercury with a burning glass; he was the last great defender of the phlogiston theory.

Lavoisier's contribution to chemistry is similar to what Newton contributed to physics. Lavoisier' radically reinterpreted the work of Priestley, Black, and Cavendish though he did not discover anything of his own. He was basically a theoretician. He recognized the true nature of combustion, introduced a new chemical nomenclature, and wrote the first modern chemistry textbook. He erroneously believed that all acids contain oxygen.

Principles of Modern Chemistry

Matter

Atom: Atom is the basic unit of a chemical element. Atom is an extremely small      particle of which we, and everything around us, are made. It consists of a dense core called the atomic nucleus surrounded by a space called the electron cloud.

Element: A chemical element, or an element, is a material which cannot be broken down or changed into another substance using chemical means. Elements may be thought of as the basic chemical building blocks of matter.

Compound: A chemical compound is a chemical substance formed by chemical union of two or more elements or ingredients in definite proportion by weight. For example, water is a compound containing hydrogen and oxygen in the ratio of two to one.

Substance: chemical substance is a material produced by or used in a reaction involving changes in atoms or molecules. Most of the substances we encounter in our daily life are some kind of mixture; for example: air, alloys, biomass, etc.

 Molecule: A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound. Molecules are made up of atoms that are held together by chemical bonds. These bonds form as a result of the sharing or exchange of electron s among atoms.

 Mole and amount of substance:  A mole is the base unit of quantity of a substance in the metric system. A mole is the quantity of a substance that contains 6.02 x 1023 units. A "unit" is the smallest measurable entity in the substance, generally either an atom or a molecule.

Properties

Ions and salts: An ion is an atom or molecule with more or less electrons than usual, giving it a positive or negative electric charge. Because an ion "wants" to become neutral by acquiring or losing additional electrons, it has interesting chemical features. Ions usually come in the form of solutions. There are three types of ions -- anions, which are negatively charged, cations, which are positively charged, and radicals, or radical ions, which are highly reactive due to having a large amount of free electrons. An ion solution is typically created when certain molecules, such as salt, are dissolved in water.

Acidity and basicity: A substance can often be classified as an acid or a base. There are several different theories which explain acid-base behavior. The simplest is Arrhenius theory, which states than an acid is a substance that produces hydronium ions when it is dissolved in water, and a base is one that produces hydroxide ions when dissolved in water.

Phase: Phase is a physically distinctive form of matter, such as a solid, liquid, gas or plasma. A phase of matter is characterized by having relatively uniform chemical and physical properties. . The most familiar examples of phases are solids, liquids, and gases. Many substances exhibit multiple solid phases. For example, there are three phases of solid iron (alpha, gamma, and delta) that vary based on temperature and pressure.

Bonding: Chemical bonding happens when atoms from two or more different elements combine to form a new substance.

Reaction: In chemistry, a reaction happens when two or more molecules interact and the molecules change. A reaction could include ions, compounds, or molecules of a single element. A chemical reaction is therefore a concept related to the 'reaction' of a substance when it comes in close contact with another, whether as a mixture or a solution; exposure to some form of energy, or both.

Redox:  Redox reactions, or oxidation-reduction reactions, primarily involve the transfer of electrons between two chemical species.

Equilibrium: A chemical equilibrium takes place when the reactants and products are in a constant ratio in a substance. The forward reaction and the reverse reactions occur at the same rate when a system is in equilibrium.

Energy: Energy is central to our understanding of chemistry, for atoms adopt arrangements that correspond to the lowest possible energy and electrons in atoms adopt the lowest possible energy distribution. Since a chemical transformation is accompanied by a change in one or more of these kinds of structures, it is invariably accompanied by an increase or decrease of energy of the substances involved.

Importance of Chemistry

Chemistry fits into our lives. Chemistry contributes to our existence, our culture, and our quality of life. Chemistry is concerned with the changes we see around us, like the rusting of iron, growing of grass, burning of wood and many more. Without these changes or chemical reactions our Planet Earth would be lifeless. It plays a critical role in man’s attempt to feed the world population, to tap new sources of energy, to clothe and house humankind, to provide renewable substitutes for dwindling or scarce materials, to improve health and conquer disease, and to monitor and protect our environment. Because of this responsiveness to human needs, chemistry has become a crucial factor in the nation’s economic well-being.  The importance of chemistry can be realized with the help of following points:

• Chemistry helps us to know that energy can be converted from one form to the other through the laws of thermodynamics.
• The knowledge of chemistry enables us to indicate harmful substances that are dangerous to our body.
• It helps us to know what the composition of one particular thing is.
• With the help of chemistry, we are able to make new substances combining different elements. This new substance will help us in maintaining good life. such as medicines
• It is important because it help to explore thing that we hadn't knew before.   

Sub-discipline

Analytical Chemistry: Analytical chemistry is the study of matter in order to reveal its composition, structure, and extent. Analytical chemistry is essential in both theoretical and applied chemistry. Analytical chemistry also is concerned with developing the tools used to examine chemical compositions. Analytical methods can be divided in to into two groups namely classical and instrumental. A classical method is also known as wet chemistry methods.

Biochemistry: Biochemistry is concerned with the chemical reactions that occur inside living organisms. Many look upon biochemistry as a science that underpins and explains the essential processes of life, impacting on biotechnology and bioinformatics, Cell biology and signaling, Development and disease, Energy and metabolism, Genetics, Molecular biology and Plant biology. In simple words Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms.

Inorganic Chemistry: Inorganic chemistry is a branch of chemistry that deals with the properties and behavior of inorganic compounds. Inorganic compounds are generally those that are not biological and characterized by not containing any hydrogen and carbon bonds. Inorganic chemistry is the study of the synthesis and behavior of inorganic and organometallic compounds. It has applications in every aspect of the chemical industry–including catalysis, materials science, pigments, surfactants, coatings, medicine, fuel, and agriculture. Inorganic chemists are employed in fields as diverse as the mining and microchip industries, environmental science, and education.

Organic Chemistry: Organic chemistry is that branch of chemistry that deals with the structure, properties, and reactions of compounds that contain carbon. It is a highly creative science. Organic chemistry is the study of carbon and the study of the chemistry of life. Since not all carbon reactions are organic, another way to look at organic chemistry would be to consider it the study of molecules containing the carbon-hydrogen (C-H) bond and their reactions.

Physical Chemistry: Physical Chemistry is the branch of chemistry dealing with the physical properties of chemical substances. It describes and explains how specific chemical substances look and behave in particular situations under certain temperatures and pressures. It is a scientific analysis of the properties and behavior of chemical systems primarily by physical theory and technique, as, for example, the thermodynamic analysis of macroscopic chemical phenomena.

Polymer Chemistry: Polymer chemistry is the study and manipulation of synthetic and organic chemical substances known as polymers. Polymer chemistry is the study of the chemistry of polymers. Polymers are long chained molecules that have a repeating unit in them. The chemistry of polymers includes polymer synthesis, reactions of polymers with different chemicals, physical chemistry of polymers, polymer analysis, polymer application etc.

Theoretical Chemistry: Theoretical chemistry applies chemistry and physics calculations to explain or make predictions about chemical phenomena Theoretical chemistry has large overlap with condensed matter physics and molecular physics.

Neurochemistry: Neurochemical is any organic substance that occurs in neural activity. Neurochemistry is the study of neurochemicals; including transmitters, peptides, proteins, lipids, sugars, and nucleic acids; their interactions, and the roles they play in forming, maintaining, and modifying the nervous system.

Nuclear Chemistry:Nuclear chemistry deals with the nuclei of atoms breaking apart. Nuclear chemistry is the study of how subatomic particles come together and make nuclei. Modern Transmutation is a large component of nuclear chemistry, and the table of nuclides is an important result and tool for this field.

Career

A degree in chemistry provides you with the skills to pursue a career in a wide range of sectors. The knowledge gained through the study of chemistry opens many career pathways. The career options in chemistry are practically endless. Research shows that in 2011, six months after graduation, almost 43% of chemistry graduates were in full-time employment in the UK or overseas. A further 42% were in full-time further study or combining study with work. Chemistry contributes to almost every object that we encounter in our daily lives. It is central science and as such offers a vast array of employment opportunities. Here are just a few of the career areas chosen by chemistry graduates.

•   Agricultural Chemistry 
•   Analytical Chemistry 
•   Biochemistry 
•   Biotechnology 
•   Catalysis 
•   Chemical Education 
•   Chemical Engineering 
•   Chemical Information Specialists 
•   Chemical Sales 
•   Chemical Technology 
•   Colloid and Surface Chemistry 
•   Consulting 
•   Consumer Product Chemistry 
•   Environmental Chemistry 
•   Food and Flavor Chemistry 
•   Forensic Chemistry 
•   Geochemistry 
•   Hazardous Waste Management 
•   Inorganic Chemistry 
•   Materials Science 
•   Medicinal Chemistry 
•   Organic Chemistry 
•   Oil and Petroleum 
•   Physical Chemistry 
•   Polymer Chemistry 
•   Pulp and Paper Chemistry 
•   R&D Management 
•   Science Writing 
•   Textile Chemistry 
•   Water Chemistry

There are diversified job roles available in the market for a chemistry graduate to choose from.  A chemistry graduate can work with the capacity of a 

•   University Lecturer 
•   University Researcher 
•   Biochemist 
•   Food Scientist 
•   Environmental Chemist 
•   Materials Scientist 
•   Teacher 
•   Nuclear Scientist 
•   Analytical Chemist 
•   Forensic Scientist 
•   Forensic Consultant
•   Forensic Image Specialist
•   Clinical Biochemist
•   Crystallographers
•   Crime Scene Examiner
•   Scenes of Crime Officer
•   Formulation Chemist
•   Color Chemist
•   Health and Safety Officer
•   Process Chemist
•   Drug Designer
•   Marine Chemist
•   Petroleum Chemist
•   Patent Attorney 
•   Science writer