The word ‘chemistry’ has derived its name form an Egyptian term kēme (chem) which means ‘earth’. The study of chemistry began several thousand years ago. It is believed that alchemy is the basis of modern day inorganic chemistry. Many a times scientists refer to chemistry as the central science, as its study is essential for various other branches of science, like physics, biology, geology, astronomy etc.
Chemistry Terms and Definitions Glossary
Chemistry, as a field of study, is interesting as well as a vast subject. There are several branches of chemistry. Students studying in schools and colleges learn chemistry as a part of their science curriculum. Those students who wish to study chemistry at the advanced levels must know, that for better understanding of the overall chemistry literature, you should have clear idea about the fundamental concepts of chemistry terms and definitions. Some of the important aspects of chemistry include: study of atomic and molecular structure of various chemical substances, their characteristics, types of reactions, types of bonds formed by different elements, methods used for extraction of metals and nonmetals, different laboratory techniques etc.
Chemistry Definitions – Glossary of Chemistry Terms and Definitions
Over a period of time, chemistry definitions have undergone several changes due to development of new theories and discovery of new chemical substances and phenomena. In this section, we have included those basic chemistry terms that are relevant to modern chemistry. The chemistry glossary terms arranged in an alphabetical order are given below:
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
how to make activated charcoal and activated charcoal benefits.
activation energy: During a chemical reaction, the minimum amount of energy which is needed by the reactants to get converted into products is known as activation energy.
Acyl Group: It is a functional group of organic compounds which is usually obtained by replacing the hydroxyl group (–OH) from any carboxylic acid.
Addition Reaction: A type of chemical reaction in which an atom or a group of atoms is added to a double or triple bond compound, in order to change it into a single and double bond compound respectively.
Alcohol: An organic compound which consists of a hydroxyl group (–OH) attached to a carbon atom of an alkyl group chain.
Aldehyde: A functional group of organic compounds, consisting of one atom each of carbon, hydrogen and oxygen. Here, the carbon atom forms a single bond with the hydrogen atom and is bonded to the oxygen atom with the help of a double bond.
Aliphatic: An organic compound in which the carbon atoms are bonded together in the form of a chain. It does not have aromatic rings.
Alkali Metals: Elements which belong to Group IA of the periodic table.
Alkaline Earth Metals: Elements which belong to Group IIA of the periodic table. Learn more about: alkaline earth metals.
Alkanes: Alkanes are a series of organic compounds, consisting of carbon and hydrogen atoms, where all the carbon atoms are bonded to each other only by single bonds.
Alkenes (Olefins): Unsaturated organic compounds which have at least one carbon-carbon double bond.
Alkynes: A type of unsaturated hydrocarbon compound which has at least one carbon-carbon triple bond.
Allotrope: Two or more elements with same physical components but different structural forms. The physical and chemical properties of various allotropic forms of an element are totally different from each other.
Alpha Particle: A positively charged particle with a charge of 2+. It contains two protons and two neutrons, like the nucleus of a helium atom.
Alum: It is a white crystalline compound of aluminum. Hydrated aluminum potassium sulfate is commonly known as alum. Its chemical formula is Kal(SO4)2.12H2O.
Ammonia: Ammonia is an inorganic compound made of nitrogen and hydrogen atoms and is chemically represented by the formula NH3.
Anion: A negatively charged particle or ion.
Aromatic Hydrocarbons: Aromatic hydrocarbon is a type of hydrocarbon compound, which has at least one structural ring of 6-carbon atoms.
Atom: The smallest structural unit of any chemical element is called an atom.
Atomic Number: The number of protons present in the nucleus of an atom.
Aufbau (‘building up’) Principle: It is the law that governs electronic configuration in the orbitals of an atom.
Avogadro’s Number: Also known as Avogadro’s constant. It is the number of particles present in one mole of any substance. It is equal to 6.023×10^23.
timeline of atomic structure.
Boiling Point: The temperature at which the atmospheric pressure and the vapor pressure of the liquid becomes equal is called the boiling point.
Boyle’s Law: Boyle’s law states that at constant temperature the pressure and volume of a given amount of gas is inversely proportional to each other.
Branched Chain Alkane: Those compounds of alkane that form branches, as a result of bonding the main chain of the molecule with functional groups are called branched chain alkanes.
Brownian motion: The zigzag motion of the tiny particles, suspended in a fluid substance is called Brownian motion.
Buffer Solution: A solution that shows resistance towards change in pH value. Basically, it is either made of a weak acid and a conjugate base or a weak base and a conjugate acid.
Butanol: An organic compound which consists of four carbon atoms bonded with each other by single bonds and one alcohol or hydroxyl group.
chemical element.
Chemical Reaction: The process by which atoms of one or more chemical substances interact with each other, to produce new products with different composition and properties. Learn more on: types of chemical reaction.
Combustion: Combustion is a chemical process in which a reaction takes place between a fuel and an oxidizer and a large amount of heat and light is released.
Covalent Bond: A type of chemical bond in which sharing of electrons takes place between the reacting atoms.
Crystallization: The process which leads to the formation of regular shaped crystals naturally or artificially.
Dalton’s atomic theory states that elements are made up of very small particles called atoms. It also states that atoms of every element are identical.
Deliquescent: The property of a substance to readily absorb the moisture present in atmosphere and converting into liquid is known as deliquescent.
Deuterium: Deuterium is an isotope of hydrogen which is heavier than common hydrogen. This is because, deuterium has one neutron in its nucleus which is not present in the nucleus of an ordinary hydrogen.
Displacement Reaction: A type of chemical reaction in which one element of a compound is displaced by another, to form a new compound.
Distillation: The physical process of separation of various components of a mixture of liquids, on the basis of their different boiling points is called distillation. Learn more on: types of distillation.
Donor Atom: A donor atom is the one that shares or donates its electrons to a Lewis acid to form a coordination complex.
Double Bond: A type of covalent bond in which double pairs of electrons are shared between two reacting atoms.
Double Salt: A salt that consists of two or more cations or anions. When in a dissolved state, double salt ionizes to form two different salts but it becomes one substance as it is crystallized.
Dry Cells: An electrochemical cell in which the electrolyte is not in a liquid form but is in the form of a paste with low moisture content.
what are subatomic particles.
Electron Affinity: Electron affinity of an atomic or molecular particle is the energy change that takes place as a result of addition or deletion of an electron from a neutrally charged atom or molecule.
Electron Configuration: The arrangement of electrons in the orbitals of an atom is known as electron configuration.
Electronegativity: In a covalent bond between two dissimilar atoms, electronegativity can be defined as the capacity of the atom of an element to draw the valence electrons towards itself.
Emulsion: An emulsion is a mixture of two or more liquid substances where the components are non-miscible with each other.
Endothermic Reaction: A type of chemical reaction which absorbs heat energy during the process.
Enthalpy: Enthalpy is a thermodynamic property of a substance used to quantify the heat content of its any given amount.
Entropy: Entropy is a thermodynamic property, used to measure that energy of a given system which cannot be utilized to carry out any external work.
Exothermic Reaction: A type of chemical reaction that releases heat energy during the process.
fossil fuels.
Fractional Distillation: A distillation process, where a liquid mixture whose components have varying boiling points are separated using a fractioning column in the distillation apparatus. Learn more on this in: fractional distillation.
Frasch Process: A technique used for mining and extraction of sulfur, the element from its minerals, from the underground deposits.
Free Energy, Gibbs Free Energy: In a thermodynamic system with constant temperature and pressure, free energy or Gibbs free energy is the measure of the total amount of energy that can be utilized for doing useful work.
Free Radical: Those atoms or ions or molecules which have one or more number of unpaired electrons in them are known as free radicals. Presence of free electrons in a radical makes it highly reactive substance.
Freezing Point Depression: The phenomenon that causes lowering of freezing point of a liquid solvent substance, on addition of another compound into it is known as freezing point depression.
Fuel Cells: Fuel cells are devices that can produce electrical energy by converting the chemical energy of any particular fuel. To gather more information on fuel cells read on: fuel cells.
Functional Group: In the molecule of an organic compound, a certain set of atoms characterize the chemical properties of the organic molecule. These groups of atoms are known as functional groups.
use of galvanized steel.
Gamma Ray: Gamma rays are a type of electromagnetic radiation with high energy and penetrating power and are released by atoms of radioactive elements. As it has a high penetrating power, gamma rays are used for radiation therapy to treat cancer. To know more read: radiation
Gangue: The impurities that come with the minerals of an ore, during its mining are known as gangue.
Geiger-Müller counter: Geiger-Müller counter is a special device used for detection of various ionizing radiations like beta particles, gamma rays etc.
Gel: Gel is a jelly like substance where a solid is suspended in the liquid dispersion medium.
Geometrical Isomers: Compounds with same number of atoms and same functional groups but different geometric structures are called geometric isomers.
Graham’s Law: Graham’s law establishes the relationship between molecular effusion of a gaseous substance and its molecular weight. It states that the rate of effusion of any particular gas is inversely proportional to the square root of molecular weight of the gas.
Graphite An allotropic form of element carbon, Graphite, is a good conductor of electricity and possess good lubricating properties.
Ground State: The state in which an atom or molecule or ion has the lowest energy, is termed as ground state. It signifies a stabilized form of that particle.
Group (Periodic Table): In the periodic table, the vertical columns in which elements with similar properties are placed are known as groups.
half life in nuclear chemistry.
Heat of Formation ( Δhf): The amount of heat absorbed or released due to formation of a pure chemical compound, by the reaction of its constituting elements, under constant pressure is known as heat of formation.
Heisenberg Uncertainty Principle: According to Heisenberg uncertainty principle, the momentum as well as the position of an electron in an atom cannot be determined precisely at the same time.
Henry’s Law: As per Henry’s law, when the temperature remains constant, the solubility of a gas in a liquid substance is directly proportional to the partial pressure exerted by the gas on the surface of the solution.
Hess’ Law: The law states that the energy change that takes place during a chemical or physical process, does not depend on the total number of intermediate steps needed for the completion of the process.
Heterogeneous Mixture: A heterogeneous mixture is made by combining two or more substances with different structure or phases.
Homogeneous Mixture: A type of mixture made up of substances that have uniformity in terms of composition and property.
Homologous Series: A series of organic compounds, that can be represented by a general chemical formula. Members of any homologous series have similar chemical properties.
Hund’s Rule: Hund’s rule is a guiding principle for filling up of p, d and f subshells of an atom. As per the rule, the pairing of electrons in the same sub-shell begins only after all the orbitals are filled by single electrons.
Hybridization of Orbitals: The term hybridization is used to define the merging of one set of atomic orbitals, for the formation of new orbitals.
Hydrocarbons: Hydrocarbons are simple organic compounds that are made up of hydrogen and carbon atoms only.
Hydrogenation: A chemical reaction, where addition of hydrogen takes place to double or triple bonded unsaturated organic compounds, in presence of a catalyst. In this way, the organic compounds get converted into saturated ones.
ionic bonding.
Ionization Potential: Also known as ionization potential, it can be defined as the least amount of energy required for the removal of an electron from a gaseous atom or molecule in its ground state.
Isomers: Molecules whose molecular formulas are same but the structural formulas are different are known as isomers. To learn more read on: isomers.
IUPAC: It stands for International Union of Pure and Applied Chemistry. It is an international organization that is responsible for setting up standards for naming of elements and compounds and also for symbols and physical quantities related to chemistry.
collision theory and reaction rates – explaining the factors of collision theory.
Up