Fundamentals of Chemistry: Terms and Definitions, Quizzes of Biology

Download Fundamentals of Chemistry: Terms and Definitions and more Quizzes Biology in PDF only on Docsity! TERM 1 matter DEFINITION 1 In the classical physics observed in everyday life, matter is any substance that has mass and takes up space by having volume. TERM 2 proton DEFINITION 2 A proton is a subatomic particle, symbol p or p+, with a positive electric charge of +1e elementary charge and mass slightly less than that of a neutron. TERM 3 isotope DEFINITION 3 Isotopes are variants of a particular chemical element which differ in neutron number. All isotopes of a given element have the same number of protons in each atom. TERM 4 element DEFINITION 4 Elemen often refers to the elements of chemistry, each a pure substance of one type of atom, which together make up all the matter in the universe. TERM 5 essential elements DEFINITION 5 Classical elements typically refer to the concepts in ancient Greece of earth, water, air, fire, and aether, which were proposed to explain the nature and complexity of all matter in terms of simpler substances. TERM 6 netron DEFINITION 6 Netronome' is a privately held fabless semiconductor company specializing in the design of network flow processors used for intelligent flow processing in network and communications devices, such as switches, routers and cyber security applications. TERM 7 atomic mass unit (amu) DEFINITION 7 The unified atomic mass unit or dalton is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass). TERM 8 radioactive isotope DEFINITION 8 A radionuclide is an atom that has excess nuclear energy, making it unstable. TERM 9 chemical symbol DEFINITION 9 In relation to the chemical elements, a symbol is a code for a chemical element. Many functional groups has their own chemical symbol, e.g. TERM 10 trace elements DEFINITION 10 A trace element is a chemical element whose concentration is very low (a "trace amount"). TERM 21 valence shell DEFINITION 21 In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. TERM 22 valence electrons DEFINITION 22 In chemistry, a valence electron is an electron that is associated with an atom, and that can participate in the formation of a chemical bond; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair. TERM 23 noble gases DEFINITION 23 The noble gases make up a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. TERM 24 Bohr model DEFINITION 24 In atomic physics, the Rutherford-Bohr model or Bohr model or Bohr diagram, introduced by Niels Bohr and Ernest Rutherford in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus-similar to structure of the Solar System, but with attraction provided by electrostatic forces rather than gravity. TERM 25 chemical bonds DEFINITION 25 A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. TERM 26 covalent bonds DEFINITION 26 A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. TERM 27 ionic bonds DEFINITION 27 Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. TERM 28 hydrogen bonds DEFINITION 28 A hydrogen bond is the electrostatic attraction between two polar groups that occurs when a hydrogen atom covalently bound to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F) experiences the electrostatic field of another highly electronegative atom nearby. TERM 29 van der Waals interactions DEFINITION 29 In physical chemistry, the van der Waals forces, named after Dutch scientist Johannes Diderik van der Waals, are distance- dependent interactions between atoms or molecules. TERM 30 molecule DEFINITION 30 A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. TERM 31 Lewis dot structure DEFINITION 31 Lewis structures are diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule. TERM 32 structural formula DEFINITION 32 The structural formula of a chemical compound is a graphic representation of the molecular structure, showing how the atoms are arranged. TERM 33 molecular formula DEFINITION 33 A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus and minus () signs. TERM 34 double covalent bond DEFINITION 34 A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. TERM 35 triple covalent bond DEFINITION 35 A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. TERM 46 surface tension DEFINITION 46 Surface tension is the elastic tendency of a fluid surface which makes it acquire the least surface area possible. TERM 47 adhesion DEFINITION 47 Adhesion is the tendency of dissimilar particles or surfaces to cling to one another. TERM 48 capillary action DEFINITION 48 Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. TERM 49 kinetic energy DEFINITION 49 In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. TERM 50 heat DEFINITION 50 Heat is the amount of energy flowing from one body of matter to another spontaneously due to their temperature difference, or by any means other than through work or the transfer of matter. TERM 51 temperature DEFINITION 51 Temperature is a physical quantity that expresses the subjective perceptions of hot and cold. Temperature is measured with a thermometer, historically calibrated in various temperature scales and units of measurement. TERM 52 calorie DEFINITION 52 Calories are units of energy. Various definitions exist but fall into two broad categories. The first, the small calorie, or gram calorie, is defined as the approximate amount of energy needed to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere. TERM 53 joule DEFINITION 53 The joule; symbol: J), is a derived unit of energy in the International System of Units. It is equal to the energy transferred to (or work done on) an object when a force of one newton acts on that object in the direction of its motion through a distance of one metre (1 newton metre or Nm). TERM 54 specific heat DEFINITION 54 Heat capacity or thermal capacity is a measurable physical quantity equal to the ratio of the heat added to an object to the resulting temperature change. TERM 55 heat of vaporization DEFINITION 55 The enthalpy of vaporization, also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to the liquid substance, to transform a quantity of that substance into a gas. TERM 56 evaporative cooling DEFINITION 56 An evaporative cooler is a device that cools air through the evaporation of water. TERM 57 solution DEFINITION 57 In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. TERM 58 solute DEFINITION 58 In chemistry, a solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. TERM 59 solvent DEFINITION 59 A solvent is a substance that dissolves a solute (a chemically distinct liquid, solid or gas), resulting in a solution. TERM 60 aqueous solution DEFINITION 60 An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant chemical formula.