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词条 Glossary of chemistry terms
释义

  1. A

  2. B

  3. C

  4. D

  5. E

  6. F

  7. G

  8. H

  9. I

  10. J

  11. K

  12. L

  13. M

  14. N

  15. O

  16. P

  17. Q

  18. R

  19. S

  20. T

  21. U

  22. V

  23. W

  24. X

  25. Y

  26. Z

  27. See also

  28. External links

{{TopicTOC-Chemistry}}

This glossary of chemistry terms is a list of terms and definitions relevant to chemistry, including chemical laws, diagrams and formulae, laboratory tools, glassware, and equipment. Chemistry is a physical science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions; it has an extensive vocabulary and a significant amount of jargon.

Note: All periodic table references refer to the IUPAC Style of the Periodic Table.
{{compact ToC|side=yes|center=yes|nobreak=yes|seealso=yes|refs=yes|extlinks=yes}}

A

{{glossary}}

{{term|absolute zero}}

{{defn|defn=A theoretical condition concerning a system at the lowest limit of the thermodynamic temperature scale, or zero {{gli|kelvin|kelvins}}, where a system does not emit or absorb energy (i.e. all {{gli|atom|atoms}} are at rest). By extrapolating the {{gli|ideal gas law}}, the internationally accepted value for absolute zero has been determined as {{convert|-273.15|C|F K}}.}}

{{term|absorbance}}

{{defn|}}

{{term|abundance}}

{{defn|}}

{{term|accuracy}}

{{defn|How close a measured value is to the actual or true value. Compare {{gli|precision}}.}}

{{term|acid}}

{{defn|A compound which, when dissolved in {{gli|water}}, gives a {{gli|pH}} of less than 7.0, or donates a hydrogen ion.}}

{{term|acid anhydride}}

{{defn|A compound with two acyl groups bound to a single oxygen atom.}}

{{term|acid dissociation constant}}

{{ghat|Also called acid ionization constant or acidity constant.}}{{defn|A quantitative measure of the strength of an {{gli|acid}} in {{gli|solution}} expressed as an {{gli|equilibrium constant}} for a chemical {{gli|dissociation}} reaction in the context of {{gli|acid-base reaction|acid-base reactions}}. It is generally denoted by the symbol Ka.}}

{{term|actinides}}

{{ghat|Also called the actinoids.}}{{defn|The {{gli|period|periodic}} series of metallic elements with atomic numbers 89 to 103, from actinium through lawrencium.}}

{{term|activated complex}}

{{defn|A structure that forms because of a collision between molecules while new bonds are formed.}}

{{term|activation energy}}

{{defn|The minimum {{gli|energy}} which must be available to a chemical system with potential {{gli|reactant|reactants}} in order to result in a {{gli|chemical reaction}}.}}

{{term|activity series}}

{{defn|}}

{{term|actual yield}}

{{defn|}}

{{term|acyclic}}

{{defn|Containing only linear structures of atoms (particularly in {{gli|hydrocarbon|hydrocarbons}}).}}

{{term|addition reaction}}

{{defn|In organic chemistry, when two or more molecules combine to make a larger one.}}

{{term|adhesion}}

{{defn|The tendency of dissimilar particles or surfaces to cling to one another as a result of {{gli|intermolecular force|intermolecular forces}}. Contrast {{gli|cohesion}}.}}

{{term|aeration}}

{{defn|The mixing of air into a {{gli|liquid}} or a {{gli|solid}}.}}

{{term|alcohol}}

{{defn|Any {{gli|organic compound}} consisting of a {{gli|hydroxyl}} {{gli|functional group}} attached to a saturated carbon atom.}}

{{term|aldehyde}}

{{defn|Any organic compound consisting of a {{gli|carbonyl group}} attached to a hydrogen atom and any other R-group.}}

{{term|alkali metal}}

{{defn|Any of the metallic {{gli|element|elements}} belonging to {{gli|group|Group 1}} of the {{gli|periodic table}}: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).}}

{{term|alkaline earth metal}}

{{defn|Any of the metallic {{gli|element|elements}} belonging to {{gli|group|Group 2}} of the {{gli|periodic table}}: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).}}

{{term|alkane}}

{{defn|Any saturated acyclic {{gli|hydrocarbon}}.}}

{{term|alkene}}

{{defn|An unsaturated {{gli|hydrocarbon}} containing at least one pair of {{gli|double bond|double-bonded}} carbons.}}

{{term|alkyl group}}

{{defn|A functional group consisting of an {{gli|alkane}} missing a hydrogen atom.}}

{{term|alkyne}}

{{defn|An unsaturated {{gli|hydrocarbon}} containing at least one pair of {{gli|triple bond|triple-bonded}} carbons.}}

{{term|allomer}}

{{defn|A substance that differs in chemical composition but has the same {{gli|crystal|crystalline}} structure as another substance.}}

{{term|allotrope}}

{{defn|Elements that can have different structures (and therefore different forms), such as carbon (diamonds, graphite, and fullerene).}}

{{term|alloy}}

{{defn|A {{gli|mixture}} of {{gli|metal|metals}} or of a metal and another {{gli|element}} which in combination exhibit a {{gli|metallic bonding}} character. Common examples include bronze, brass, and pewter.}}

{{term|amalgam}}

{{defn|}}

{{term|amplitude}}

{{defn|The maximum distance that the particles of the medium carrying the wave move away from their rest position.}}{{term|analyte}}{{defn|}}{{term|analytical chemistry}}{{defn|}}

{{term|anion}}

{{defn|A negatively charged {{gli|ion}}.}}

{{term|anode}}

{{defn|no=1|An {{gli|electrode}} through which the conventional electric current (the flow of positive charges) enters into a {{gli|polarity|polarized}} electrical circuit.}}{{defn|no=2|The wire or plate of an {{gli|electrochemical cell}} having an excess positive charge. Negatively charged {{gli|anion|anions}} always move toward the anode. Compare {{gli|cathode}}.}}

{{term|aqueous solution}}

{{defn|A {{gli|solution}} in which the {{gli|solvent}} is {{gli|water}}. It is denoted in chemical equations by appending (aq) to a {{gli|chemical formula}}.}}

{{term|aromaticity}}

{{defn|A chemical property of conjugated rings of atoms, such as {{gli|benzene}}, which results in unusually high stability.}}

{{term|atom}}

{{defn|A chemical element in its smallest form, made up of {{gli|proton|protons}} and {{gli|neutron|neutrons}} within the nucleus and {{gli|electron|electrons}} circling the nucleus.}}

{{term|atomic mass}}

{{defn|The {{gli|mass}} of an {{gli|atom}}, typically expressed in {{gli|unified atomic mass unit|unified atomic mass units}} and nearly equivalent to the {{gli|mass number}}.}}

{{term|atomic mass unit}}

{{defn|See {{gli|unified atomic mass unit}}.}}

{{term|atomic number (Z)}}

{{ghat|Also called proton number.}}{{defn|The number of {{gli|proton|protons}} found in the {{gli|nucleus}} of an {{gli|atom}} of a given {{gli|element|chemical element}}. It is identical to the charge number of the nucleus and is used in the {{gli|periodic table}} to uniquely identify each chemical element.}}

{{term|atomic orbital}}

{{defn|the region where the electron of the atom may be found}}

{{term|atomic radius}}

{{defn|}}

{{term|atomic weight}}

{{defn|}}

{{term|average atomic mass}}

{{defn|}}

{{term|Avogadro's law}}

{{defn|}}

{{term|Avogadro's number}}

{{defn|The number of particles in one {{gli|mole}} of a substance, defined as exactly 6.022{{e|23}} particles.}}

{{term|azeotrope}}

{{defn|A {{gli|mixture}} of {{gli|liquid|liquids}} whose composition is unchanged by {{gli|distillation}}.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

B

{{glossary}}

{{term|barometer}}

{{defn|A device used to measure atmospheric pressure.}}

{{term|base}}

{{defn|A substance that accepts a {{gli|proton}} and has a {{gli|pH}} above 7.0. A common example is sodium hydroxide (NaOH).}}

{{term|base anhydride}}

{{defn|Oxides of group I and II metal elements.}}

{{term|beaker}}

{{defn|}}

{{term|Beer–Lambert law}}

{{defn|}}

{{term|biochemistry}}

{{defn|The study of the chemistry of biological systems and organisms.}}

{{term|Bohr model}}

{{defn|}}

{{term|boiling}}

{{defn|See {{gli|vaporization}}.}}

{{term|boiling point}}

{{defn|The temperature at which a liquid substance starts to boil.}}

{{term|boiling-point elevation}}

{{defn|the process where the boiling point is elevated by adding a substance}}

{{term|bond}}

{{defn|The attraction and repulsion between atoms and molecules that is a cornerstone of chemistry.}}

{{term|Boyle's law}}

{{defn|for a given mass of gas at constant temperature, the volume varies inversely with the pressure}}

{{term|Bragg's law}}

{{defn|}}

{{term|Brønsted–Lowry acid}}

{{defn|Any chemical species that readily donates a {{gli|proton}}.}}

{{term|Brønsted–Lowry acid–base reaction}}

{{defn|}}

{{term|Brønsted–Lowry base}}

{{defn|Any chemical species that readily accepts a {{gli|proton}}.}}

{{term|Büchner flask}}

{{defn|}}

{{term|buckminsterfullerene}}

{{defn|}}

{{term|buffered solution}}

{{ghat|Also simply called a buffer.}}{{defn|An {{gli|aqueous solution}} consisting of a weak {{gli|acid}} and its {{gli|conjugate base}} or a weak {{gli|base}} and its {{gli|conjugate acid}} that resists changes in {{gli|pH}} when strong acids or bases are added.}}

{{term|bumping}}

{{defn|}}

{{term|bung}}

{{defn|}}

{{term|burette}}

{{ghat|Also spelled buret.}}{{defn|Glassware used to dispense specific amounts of {{gli|liquid}} when precision is necessary (e.g. during {{gli|titration|titrations}} and {{gli|resource dependent reaction|resource-dependent reactions}}).}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

C

{{glossary}}

{{term|calorimeter}}

{{defn|A device used to measure {{gli|heat}}.}}

{{term|catalyst}}

{{defn|Any element or compound that facilitates an increase in the speed of a {{gli|chemical reaction}} but which is not consumed or destroyed during the reaction. It is considered both a {{gli|reactant}} and a {{gli|product}} of the reaction.}}

{{term|cathode}}

{{defn|An {{gli|electrode}} from which the conventional electric current (the flow of positive charges) exits a {{gli|polarity|polarized}} electrical circuit. Positively charged {{gli|cation|cations}} always move toward the cathode, though the cathode's polarity can be positive or negative depending on the type of electrical device and how it is being operated. Compare {{gli|anode}}.}}

{{term|cation}}

{{defn|A positively charged {{gli|ion}}.}}

{{term|centrifugation}}

{{defn|A laboratory technique which involves the application of centrifugal force to separate particles from a {{gli|solution}} according to their size, shape, and density. Larger and/or denser substances migrate away from the axis of a {{gli|centrifuge}}, while smaller and/or less dense substances migrate towards the axis.}}

{{term|centrifuge}}

{{defn|A device used to separate substances based on size, shape, and density by {{gli|centrifugation}}, or the rotation of vessels containing the substances around a centred axis at extremely high velocities.}}

{{term|cell potential}}

{{defn|The force in a galvanic cell that pulls electrons through a reducing agent to an oxidizing agent.}}

{{term|chain reaction}}

{{defn|}}

{{term|charge number}}

{{defn|defn=A quantized value of {{gli|electric charge}} calculated as the electric charge in {{gli|coulomb|coulombs}} divided by the elementary-charge constant, or z = q/e. Charge numbers for {{gli|ion|ions}} are denoted in superscript (e.g. Na+ indicates a sodium ion with a charge number of positive one). {{gli|atomic number|Atomic numbers}} are charge numbers of {{gli|nucleus|atomic nuclei}}.}}

{{term|Charles's law}}

{{defn|When the pressure on a sample of a dry gas is held constant, the Kelvin temperature is directly proportional to its volume.}}{{term|chelating agent}}{{defn|defn=}}

{{term|chelation}}

{{defn|A type of {{gli|bond|bonding}} involving the formation of two separate {{gli|coordinate covalent bond|coordinate covalent bonds}} between a {{gli|denticity|polydentate}} {{gli|ligand}} and a single central {{gli|metal}} {{gli|ion}}. The ligand is usually an {{gli|organic compound}} called a chelant or {{gli|chelating agent}}.}}

{{term|chemical composition}}

{{defn|The identity and relative number of the {{gli|element|elements}} that make up a {{gli|compound|chemical compound}}, which can often be expressed with a {{gli|chemical formula}}.}}

{{term|chemical formula}}

{{defn|Any of various means of concisely displaying information about the {{gli|chemical composition}} of a {{gli|compound}} or {{gli|molecule}} using letters, numbers, and/or typographical symbols. Chemical formulas, such as {{gli|empirical formula|empirical}} and {{gli|molecular formula|molecular formulas}}, can only indicate the identities and numerical proportions of the atoms in a compound and are therefore more limited in descriptive power than {{gli|chemical nomenclature|chemical names}} and {{gli|structural formula|structural formulas}}.}}

{{term|chemical law}}

{{defn|A law of nature relevant to {{gli|chemistry}}, such as the {{gli|law of conservation of mass}}.}}

{{term|chemical nomenclature}}

{{defn|}}

{{term|chemical process}}

{{defn|}}

{{term|chemical reaction}}

{{defn|The change of one or more {{gli|chemical substance|substances}} into one or more different substances.}}

{{term|chemical species}}

{{defn|A {{gli|chemical substance}} or ensemble of substances composed of chemically identical molecular entities which can explore the same set of molecular energy levels on a characteristic or delineated time scale.}}

{{term|chemical substance}}

{{ghat|Also called a pure substance or simply a substance.}}{{defn|A form of {{gli|matter}} that has constant {{gli|chemical composition}} and characteristic {{gli|physical property|properties}} and which cannot be separated into simpler components by purely physical methods (i.e. without breaking {{gli|bond|chemical bonds}}). It is often called a pure substance to distinguish it from a {{gli|mixture}}.}}

{{term|chemistry}}

{{defn|The scientific discipline that studies {{gli|chemical substance|chemical substances}}, {{gli|compound|compounds}}, and {{gli|molecule|molecules}} composed of {{gli|atom|atoms}} of various {{gli|element|chemical elements}}, as well as their {{gli|chemical composition|compositions}}, structures, properties, behaviors, and the changes they undergo during {{gli|chemical reaction|reactions}} with other substances.}}

{{term|chirality}}

{{defn|}}

{{term|cis–trans isomerism}}

{{defn|}}

{{term|closed system}}

{{defn|}}

{{term|cohesion}}

{{defn|The tendency of similar particles or surfaces to cling to one another as a result of {{gli|intermolecular force|intermolecular forces}}. Contrast {{gli|adhesion}}.}}

{{term|colligative property}}

{{defn|A property of {{gli|solution|solutions}} that depends upon the ratio of the number of {{gli|solute}} particles to the number of {{gli|solvent}} particles in the solution, and not on the nature of the {{gli|chemical species}} present.}}

{{term|colloid}}

{{defn|A mixture of evenly dispersed substances, such as many milks.}}

{{term|combustion}}

{{defn|An {{gli|exothermic process|exothermic}} reaction between an {{gli|oxidant}} and a fuel that produces large amounts of heat and often light.}}

{{term|Commission on Isotopic Abundances and Atomic Weights (CIAAW)}}

{{defn|}}

{{term|compression}}

{{defn|An area in a longitudinal wave where the particles are closer and pushed in.}}

{{term|compound}}

{{defn|A {{gli|chemical substance|substance}} that is made up of two or more {{gli|bond|chemically bonded}} {{gli|element|elements}}.}}

{{term|concentration}}

{{defn|The abundance of a constituent of a {{gli|mixture}} divided by the total {{gli|volume}} of the mixture. Several different definitions of concentration are widely used in chemistry, including {{gli|mass concentration}}, {{gli|volume concentration}}, and {{gli|molar concentration}}.}}

{{term|condensation}}

{{defn|The {{gli|phase transition}} of a substance from a {{gli|gas}} to a {{gli|liquid}}.}}

{{term|condosity}}

{{defn|A comparative measurement of the electrical conductivity of a {{gli|solution}} defined as the molar concentration of a sodium chloride (NaCl) solution that has the same specific electrical conductance as the solution under test and expressed in units of moles per unit volume.}}

{{term|conductor}}

{{defn|Any object or material that allows the flow of an {{gli|electric current}} in one or more directions. Contrast {{gli|insulator}}.}}

{{term|conformation}}

{{defn|The spatial arrangement of atoms affording distinction between {{gli|stereoisomer|stereoisomers}} which can be interconverted by rotations about formally {{gli|single bond|single bonds}}.}}

{{term|conjugate acid}}

{{defn|}}

{{term|conjugate base}}

{{defn|}}

{{term|conjugated system}}

{{defn|}}

{{term|cooling curve}}

{{defn|}}

{{term|coordinate chemistry}}

{{defn|}}

{{term|coordinate covalent bond}}

{{defn|}}

{{term|coordination complex}}

{{defn|}}

{{term|corrosion}}

{{defn|An irreversible interfacial {{gli|chemical reaction}} of a material with its environment which results in consumption of the material or {{gli|dissolution}} into the material of an external component of the environment.}}

{{term|coulomb}}

{{defn|The {{gli|SI}} unit of {{gli|electric charge}} (symbol: C), defined as the charge transported by a constant {{gli|electric current|current}} of one ampere in one second.}}

{{term|covalent bond}}

{{ghat|Also called a molecular bond.}}{{defn|A {{gli|bond}} that involves the sharing of {{gli|electron pair|electron pairs}} between {{gli|atom|atoms}}. The stable balance of attractive and repulsive forces that occurs between atoms when they share electrons is known as covalent bonding.}}

{{term|crest}}

{{defn|The highest point in a wave.}}

{{term|critical mass}}

{{defn|}}

{{term|critical point}}

{{defn|The end point of a {{gli|phase}} equilibrium curve or {{gli|pressure}}-{{gli|temperature}} curve at which conditions are such that phase boundaries vanish and a substance's different phases, such as {{gli|liquid}} and {{gli|vapor}}, can coexist. The critical point is defined by the intersection of a critical temperature, Tc, and a critical pressure, pc; above this temperature and pressure, all distinction between phases disappears and the substance becomes a {{gli|supercritical fluid}}.}}

{{term|crystal}}

{{defn|A {{gli|solid}} whose constituent particles (such as atoms, ions, or molecules) are arranged in an orderly periodic microscopic structure, forming a {{gli|lattice}} that extends in all directions.}}

{{term|crystallography}}

{{defn|}}

{{term|cuvette}}

{{defn|A type of glassware used in {{gli|spectroscopy|spectroscopic}} experiments. It is usually made of plastic, glass, or quartz and should be as clean and clear as possible.}}

{{term|cyclotron}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

D

{{glossary}}

{{term|d-block}}

{{defn|}}

{{term|Dalton's law of partial pressures}}

{{defn|}}

{{term|deionization}}

{{defn|The removal of ions, and in water's case, mineral ions such as sodium, iron and calcium.}}

{{term|deliquescence}}

{{defn|A substance's affinity for water, often characterized as its tendency to absorb moisture from the atmosphere to form {{gli|aqueous solution|aqueous solutions}}. Most strongly deliquescent substances are {{gli|salt|salts}}, such as calcium chloride and potassium carbonate.}}

{{term|delocalized electron}}

{{defn|}}

{{term|density}}

{{defn|defn=An {{gli|intensive property}} of a substance defined as {{gli|mass}} per unit {{gli|volume}} and expressed by the equation d = m/V.}}

{{term|denticity}}

{{defn|The number of donor groups in a single {{gli|ligand}} that bind to a central atom in a {{gli|coordination complex}}.}}

{{term|dependent variable}}

{{defn|}}

{{term|deposition}}

{{defn|The settling of particles within a solution or mixture.}}

{{term|Dewar flask}}

{{defn|See {{gli|vacuum flask}}.}}

{{term|diatomic}}

{{defn|Composed of two atoms.}}

{{term|diatomic molecule}}

{{defn|Any {{gli|molecule}} composed of only two {{gli|atom|atoms}}, of the same or different {{gli|element|elements}}.}}

{{term|diffusion}}

{{defn|}}

{{term|dimer}}

{{defn|}}

{{term|dipolar bond}}

{{defn|}}

{{term|dipole}}

{{defn|The electric or magnetic separation of charge.}}

{{term|dipole moment}}

{{defn|The polarity of a polar covalent bond.}}

{{term|dispersion}}

{{defn|}}

{{term|dissociation}}

{{defn|}}

{{term|dissolution}}

{{ghat|Also called solvation.}}{{defn|The interaction of a {{gli|solvent}} with the molecules or ions of a {{gli|solute}}, involving bond formation, {{gli|hydrogen bond|hydrogen bonding}}, and {{gli|van der Waals force|van der Waals forces}}.}}

{{term|distillation}}

{{defn|}}

{{term|double bond}}

{{defn|A {{gli|bond}} involving the {{gli|covalent bond|covalent}} sharing of two {{gli|electron pair|pairs of electrons}}.}}

{{term|double-replacement reaction}}

{{defn|}}

{{term|ductility}}

{{ghat|Also called malleability.}}{{defn|A measure of a material's ability to undergo significant plastic deformation before rupturing, typically expressed as percent elongation or percent area reduction from a tensile test and popularly characterized by the material's ability to be stretched into a wire.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

E

{{glossary}}

{{term|earth metal}}

{{defn|See {{gli|alkaline earth metal|alkaline earth metal}}.}}

{{term|electrolyte}}

{{defn|A {{gli|solution}} that conducts a certain amount of electric current and can be split categorically into weak and strong electrolytes.}}

{{term|electrochemical cell}}

{{defn|Using a chemical reaction's current, {{gli|electromotive force}} is made.}}

{{term|electromagnetic radiation}}

{{defn|A type of wave that can go through vacuums as well as material and is classified as a self-propagating wave.}}

{{term|electromagnetic spectrum}}

{{defn|}}

{{term|electromagnetism}}

{{defn|Fields with an electric charge and electrical properties that change the way that particles move and interact.}}

{{term|electromotive force}}

{{defn|A device that gains energy as {{gli|electric charge|electric charges}} pass through it.}}

{{term|electron}}

{{defn|A subatomic particle with a net charge that is negative.}}

{{term|electron configuration}}

{{defn|}}

{{term|electron pair}}

{{defn|Two {{gli|electron|electrons}} which occupy the same {{gli|molecular orbital}} but have opposite spins. Electron pairs form {{gli|bond|chemical bonds}} or occur as {{gli|lone pair|lone pairs}} of {{gli|valence electron|valence electrons}}; it is also possible for electrons to occur as {{gli|unpaired electron|unpaired electrons}}.}}

{{term|electron shell}}

{{defn|An orbital around an atom's nucleus containing a fixed number of {{gli|electron|electrons}} (usually two or eight).}}

{{term|electronegativity}}

{{defn|}}

{{term|electric charge}}

{{defn|A measured property ({{gli|coulomb|coulombs}}) that determines electromagnetic interaction.}}

{{term|element}}

{{defn|A species of {{gli|atom|atoms}} having the same number of {{gli|proton|protons}} in their {{gli|nucleus|atomic nuclei}} and hence the same {{gli|atomic number}}. Chemical elements constitute all of the ordinary {{gli|matter}} in the universe; 118 elements have been identified and are organized by their various chemical properties in the {{gli|periodic table|periodic table of the elements}}.}}

{{term|enantiomer}}

{{defn|}}

{{term|enantiomorph}}

{{defn|}}

{{term|endothermic process}}

{{defn|}}

{{term|energy}}

{{defn|A system's ability to do {{gli|work}}.}}

{{term|enthalpy}}

{{defn|A measure of the total energy of a thermodynamic system, usually symbolized as H.}}

{{term|enthalpy of fusion}}

{{defn|}}

{{term|entropy}}

{{defn|The amount of energy not available for work in a closed thermodynamic system. Usually symbolized as S.}}

{{term|environmental chemistry}}

{{defn|}}

{{term|enzyme}}

{{defn|A protein {{gli|catalyst}} that speeds up a chemical reaction.}}

{{term|empirical formula}}

{{defn|Also called the simplest formula, gives the simplest whole-number ratio of atoms of each element present in a compound.}}

{{term|equilibrium}}

{{defn|Universally, it is the condition of a system in which all competing influences are balanced. Chemical equilibrium is the state in which the concentrations of the reactants and products have stopped changing in time.}}

{{term|Eppendorf tube}}

{{defn|A generalized and trademarked name used to refer to a {{gli|microcentrifuge tube}}.}}

{{term|Erlenmeyer flask}}

{{defn|}}

{{term|exothermic process}}

{{defn|}}

{{term|extensive property}}

{{defn|}}

{{term|extraction}}

{{defn|}}

{{term|extrinsic property}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

F

{{glossary}}

{{term|f-block}}

{{defn|}}

{{term|freezing}}

{{defn|The {{gli|phase transition}} of a substance from a {{gli|liquid}} to a {{gli|solid}}.}}

{{term|Faraday constant}}

{{defn|defn=A unit of {{gli|electric charge}} widely used in {{gli|electrochemistry}} and equal to approximately  96,500 {{gli|coulomb|coulombs}}. It represents 1 {{gli|mole}} of {{gli|electron|electrons}}: 6.022 × 1023 electrons. F = 96 485.339 9(24) C/mol.}}

{{term|Faraday's laws of electrolysis}}

{{defn|A two-part law that Michael Faraday published about electrolysis. The mass of a substance altered at an electrode during electrolysis is directly proportional to the quantity of electricity transferred at that electrode; the mass of an elemental material altered at an electrode is directly proportional to the element's equivalent weight.}}

{{term|Fick's laws of diffusion}}

{{defn|}}

{{term|filtrate}}

{{defn|}}

{{term|first-order reaction}}

{{defn|}}

{{term|flask}}

{{defn|A vessel or container, most commonly a type of glassware, widely used in laboratories for a variety of purposes, such as preparing, holding, containing, collecting, or volumetrically measuring chemicals, samples, or solutions, or as a chamber in which a {{gli|chemical reaction}} occurs. Flasks come in a number of shapes and sizes but are typically characterized by a wider vessel "body" and one or more narrower tubular sections with an opening at the top.}}

{{term|formal charge}}

{{defn|}}

{{term|fractional distillation}}

{{defn|}}

{{term|free radical}}

{{defn|}}

{{term|freezing-point depression}}

{{defn|}}

{{term|frequency}}

{{defn|defn=A measurement of the number of cycles of a given process per unit of time. The {{gli|SI}} unit for measuring frequency is the hertz (Hz), with 1 Hz = 1 cycle per second.}}

{{term|functional group}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

G

{{glossary}}

{{term|galvanic cell}}

{{defn|A type of battery made up of electrochemicals with two different metals connected by a salt bridge.}}

{{term|gas}}

{{defn|One of the four fundamental {{gli|state of matter|states of matter}}, characterized by high-energy particles which fill their container but have no definite shape or volume.}}

{{term|gas chromatography}}

{{defn|}}

{{term|Gay-Lussac's law}}

{{defn|A chemical law used for each of the two relationships derived by French chemist Joseph Louis Gay-Lussac and which concern the properties of gases, though the name is more usually applied to his law of combining volumes.}}

{{term|geochemistry}}

{{defn|The study of the chemistry and chemical composition of the Earth and geological processes.}}

{{term|Gibbs energy}}

{{defn|A value that indicates the spontaneity of a reaction. Usually symbolized as G.}}

{{term|glass}}

{{defn|}}

{{term|gram-atom}}

{{defn|One gram-atom of an element is defined as a collection of 6.023X10^23 atoms.}}

{{term|Grignard reaction}}

{{defn|}}

{{term|ground glass joint}}

{{defn|An apparatus designed to quickly and easily fit two pieces of leak-tight glassware together, featuring ground glass surfaces and typically a custom-made conical taper.}}

{{term|group}}

{{ghat|Also called a family.}}{{defn|A vertical column of the {{gli|periodic table|periodic table of the elements}} and the elements that share it. Contrast {{gli|period}}.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

H

{{glossary}}

{{term|halogen}}

{{defn|Any of the five {{gli|non-metal|non-metallic}} {{gli|element|elements}} of {{gli|group|Group 17}} of the {{gli|periodic table}}: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).}}

{{term|hadron}}

{{defn|A subatomic particle of a type including the baryons and mesons that can take part in the strong interaction.}}

{{term|heat}}

{{defn|Energy transferred from one system to another by thermal interaction.}}

{{term|heat of fusion}}

{{defn|See {{gli|enthalpy of fusion}}.}}

{{term|Henry's law}}

{{defn|}}

{{term|Hess's law}}

{{defn|}}

{{term|Hund's rules}}

{{defn|}}

{{term|hydrate}}

{{defn|}}

{{term|hydration reaction}}

{{defn|}}

{{term|hydrogen}}

{{defn|}}

{{term|hydrogen bond}}

{{defn|A form of electrostatic interaction between an {{gli|electronegativity|electronegative}} {{gli|atom}} and a {{gli|hydrogen}} atom bound to a second electronegative atom. Hydrogen bonding is unique because the small size of the hydrogen atoms permits proximity of the interacting {{gli|electrical charge|electrical charges}}, and may occur as an {{gli|intermolecular force|intermolecular}} or {{gli|intramolecular force|intramolecular}} force.}}

{{term|hydrogenation}}

{{defn|}}

{{term|hydrolysis}}

{{defn|The cleavage of a {{gli|bond|chemical bond}} by the addition of {{gli|water}}.}}{{term|hygroscopy}}{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

I

{{glossary}}

{{term|ideal gas}}

{{defn|}}

{{term|ideal gas constant}}

{{ghat|Also called the universal gas constant.}}{{defn|The proportionality constant in the {{gli|ideal gas law}}, defined as 0.08206 {{gli|liter|L}}·{{gli|atmosphere|atm}}/({{gli|kelvin|K}}·{{gli|mole|mol}}).}}

{{term|ideal gas law}}

{{defn|A {{gli|chemical law}} which states that the {{gli|volume}} of a {{gli|gas}} is proportional to the amount of gas and its {{gli|kelvin|Kelvin}} {{gli|temperature}} and inversely proportional to its {{gli|pressure}}.}}

{{term|independent variable}}

{{defn|}}

{{term|indicator}}

{{defn|A special compound added to a {{gli|solution}} that changes color depending on the {{gli|acidity}} of the solution. Different indicators have different colors and are effective within different {{gli|pH}} ranges.}}

{{term|induced radioactivity}}

{{defn|radioactivity caused by bombarding a stable isotope with elemental particles, forming a radioactive isotope}}

{{term|inorganic compound}}

{{defn|Any chemical compound that does not contain {{gli|carbon}}, though there are exceptions. Contrast {{gli|organic compound}}.}}

{{term|inorganic chemistry}}

{{defn|A branch of chemistry concerning the chemical properties and reactions of {{gli|inorganic compound|inorganic compounds}}. Contrast {{gli|organic chemistry}}.}}

{{term|insulator}}

{{defn|Any material that resists the flow of an {{gli|electric current}}. Contrast {{gli|conductor}}.}}

{{term|intensive property}}

{{defn|}}

{{term|intermediate}}

{{defn|}}

{{term|intermolecular force}}

{{defn|}}

{{term|International System of Units (SI)}}

{{defn|}}

{{term|International Union of Pure and Applied Chemistry (IUPAC)}}

{{defn|An international federation of chemists that is recognized as the world authority in developing standards for {{gli|chemical nomenclature}} and other methodologies in chemistry.}}

{{term|intramolecular force}}

{{defn|}}

{{term|intrinsic property}}

{{defn|}}

{{term|ion}}

{{defn|A {{gli|molecule}} that has gained or lost one or more {{gli|electron|electrons}} from its neutral state and therefore possesses a negative or positive {{gli|electric charge}}.}}

{{term|ionic bond}}

{{defn|An electrostatic attraction between oppositely charged {{gli|ion|ions}}.}}

{{term|ionization}}

{{defn|The breaking up of a chemical {{gli|compound}} into separate ions.}}

{{term|isoelectronicity}}

{{defn|The phenomenon of two or more {{gli|chemical species}} ({{gli|atom|atoms}}, {{gli|molecule|molecules}}, {{gli|ion|ions}}, etc.) being composed of different {{gli|element|elements}} but having the same number of {{gli|valence electron|valence}} {{gli|electron|electrons}} and the same structural arrangement (i.e. the same number of atoms with the same connectivity). Isoelectronic species typically show useful consistency and predictability in their chemical properties.}}

{{term|isomer}}

{{defn|}}

{{term|isomerization}}

{{defn|}}

{{term|isotope}}

{{defn|A variant of a particular {{gli|element|chemical element}} which differs in the number of {{gli|neutron|neutrons}} present in the {{gli|nucleus}}. All isotopes of a given element have the same number of {{gli|proton|protons}} in each {{gli|atom}}.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

J

{{glossary}}

{{term|joule}}

{{defn|The {{gli|SI}} unit of {{gli|energy}} (symbol: J). One joule is defined as one Newton-meter.}}{{glossary end}}

K

{{glossary}}

{{term|kelvin}}

{{defn|The {{gli|SI}} base unit of {{gli|temperature}} (symbol: K). The Kelvin scale is an absolute thermodynamic temperature scale that uses {{gli|absolute zero}} as its null point.}}

{{term|ketone}}

{{defn|An organic compound with a {{gli|carbonyl}} group between two {{gli|carbon}} atoms.}}

{{term|kinetics}}

{{defn|A subfield of chemistry specializing in {{gli|reaction rate|reaction rates}}.}}

{{term|kinetic energy}}

{{defn|The {{gli|energy}} of an object due to its motion.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

L

{{glossary}}

{{term|lanthanides}}

{{ghat|Also called the lanthanoids.}}{{defn|The {{gli|period|periodic}} series of {{gli|metal|metallic}} elements with atomic numbers 57 through 71, from lanthanum through lutetium.}}

{{term|lattice}}

{{defn|The unique arrangement of atoms or molecules in a {{gli|crystal|crystalline}} liquid or solid.}}

{{term|lattice energy}}

{{defn|}}

{{term|law of conservation of energy}}

{{defn|}}

{{term|law of conservation of mass}}

{{defn|}}

{{term|law of multiple proportions}}

{{defn|}}

{{term|laws of thermodynamics}}

{{defn|}}

{{term|leveling effect}}

{{defn|}}

{{term|Lewis acid}}

{{defn|}}

{{term|Lewis base}}

{{defn|}}

{{term|Lewis structure}}

{{defn|}}

{{term|ligand}}

{{defn|}}

{{term|light}}

{{defn|The portion of the {{gli|electromagnetic spectrum}} which is visible to the unaided human eye. Also referred to as visible light.}}

{{term|liquefaction}}

{{defn|}}

{{term|liquid}}

{{defn|One of the four fundamental {{gli|state of matter|states of matter}}, characterized by nearly incompressible fluid particles that retain a definite volume but no fixed shape.}}

{{term|London dispersion forces}}

{{defn|A type of weak {{gli|intermolecular force}}.}}

{{term|Newton's laws of motion}}

{{defn|An object in motion stays in motion; an object at rest stays at rest unless an unbalanced force acts upon it.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

M

{{glossary}}

{{term|magnetic quantum number}}

{{defn|}}

{{term|malleability}}

{{defn|See {{gli|ductility}}.}}

{{term|manometer}}

{{defn|An instrument used to measure {{gli|pressure}} invented by Evangelista Torricelli in 1643.}}

{{term|mass}}

{{defn|A {{gli|physical property|property}} of physical {{gli|matter}} that is a measure of its resistance to acceleration when a net force is applied. The {{gli|SI}} base unit for mass is the kilogram (kg).}}

{{term|mass concentration}}

{{defn|}}

{{term|mass fraction}}

{{defn|}}

{{term|mass number (A)}}

{{ghat|Also called atomic mass number or nucleon number.}}{{defn|The total number of {{gli|proton|protons}} and {{gli|neutron|neutrons}} (together known as nucleons) within the {{gli|nucleus}} of an {{gli|atom}}. It determines the {{gli|atomic mass}} of the atom. Mass number varies between different {{gli|isotope|isotopes}} of the same chemical element, and is often included either after the element's name (as in carbon-12) or as a superscript to the left of the element's symbol (as in 12C) to identify a specific isotope.}}

{{term|mass spectrometry}}

{{defn|}}

{{term|matter}}

{{defn|Any substance that has {{gli|mass}} and takes up space by having {{gli|volume}}.}}

{{term|metal}}

{{defn|Any chemical element which is a good {{gli|conductor}} of both {{gli|electricity}} and {{gli|heat}} and which readily forms {{gli|cation|cations}} and {{gli|ionic bond|ionic bonds}} with {{gli|non-metal|non-metals}}.}}

{{term|melting}}

{{defn|The {{gli|phase transition}} of a substance from a {{gli|solid}} to a {{gli|liquid}}.}}

{{term|melting point}}

{{defn|}}

{{term|metalloid}}

{{defn|A chemical element or substance possessing properties of both {{gli|metal|metals}} and {{gli|non-metal|non-metals}}.}}

{{term|methylene blue}}

{{defn|A heterocyclic {{gli|aromaticity|aromatic}} {{gli|compound}} with the {{gli|molecular formula}} {{gli|carbon|C}}16{{gli|hydrogen|H}}18{{gli|nitrogen|N}}3SCl.}}

{{term|microcentrifuge tube}}

{{defn|A small plastic container that is used to store small amounts of liquid.}}

{{term|mineral}}

{{defn|}}

{{term|miscibility}}

{{defn|}}

{{term|mixture}}

{{defn|A material made up of two or more different substances which are mixed physically but are not combined chemically (i.e. a chemical reaction has not taken place which has changed the molecules of the substances into new substances).}}

{{term|moiety}}

{{defn|}}

{{term|molality}}

{{defn|}}

{{term|molar attenuation coefficient}}

{{defn|}}

{{term|molar mass}}

{{defn|}}

{{term|molarity}}

{{defn|}}

{{term|mole}}

{{defn|A unit (symbol: mol) that measures the amount of a {{gli|chemical substance|substance}} in terms of the absolute number of particles or entities composing the substance. A single mole contains approximately {{gli|Avogadro's number|6.022×1023}} particles or entities.}}

{{term|molecular formula}}

{{defn|}}

{{term|molecular orbital}}

{{defn|The region where an electron can be found in a {{gli|molecule}} (as opposed to an atom).}}

{{term|molecular orbital diagram}}

{{defn|}}

{{term|molecule}}

{{defn|A number of atoms that are chemically bonded together and collectively electrically neutral.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

N

{{glossary}}

{{term|natural abundance}}

{{defn|}}

{{term|neat}}

{{defn|conditions with a liquid reagent or gas performed with no added solvent or cosolvent}}

{{term|neutron}}

{{defn|A neutral unit or subatomic particle that has no net charge.}}

{{term|neutrino}}

{{defn|a particle that can travel at speeds close to the speed of light and are created as a result of radioactive decay}}

{{term|nitrogen}}

{{defn|}}

{{term|nucleus}}

{{defn|The centre of an {{gli|atom}}, made up of {{gli|neutron|neutrons}} and {{gli|proton|protons}} and possessing a net positive electric charge.}}

{{term|noble gas}}

{{defn|Any of the six {{gli|non-metal|non-metallic}} {{gli|element|elements}} of {{gli|group|Group 18}} of the {{gli|periodic table}}: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). All of the noble gases have outer {{gli|electron shell|electron shells}} that are completely filled in their naturally occurring states, giving them very low chemical reactivity.}}

{{term|non-metal}}

{{defn|Any chemical element which is not a {{gli|metal}}.}}

{{term|nuclear}}

{{defn|Of or pertaining to the {{gli|nucleus|atomic nucleus}}.}}

{{term|nuclear chemistry}}

{{defn|The branch of chemistry that studies the various processes and properties relevant to {{gli|nucleus|atomic nuclei}}, including {{gli|radioactivity}}.}}

{{term|nuclear magnetic resonance spectroscopy}}

{{defn|A technique that exploits the magnetic properties of certain nuclei, useful for identifying unknown compounds. Nuclear magnetic resonance is often abbreviated NMR.}}

{{term|nuclear transmutation}}

{{defn|}}

{{term|nuclide}}

{{defn|A species of {{gli|atom}} characterized by its {{gli|mass number}}, {{gli|atomic number}}, and nuclear energy state, provided that the mean life in that state is long enough to be observable.}}

{{term|number density}}

{{defn|A measure of the {{gli|concentration}} of countable objects (atoms, molecules, etc.) in space, expressed as the number per unit {{gli|volume}}.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

O

{{glossary}}

{{term|octet rule}}

{{ghat|Also called the Lewis octet rule.}}{{defn|A classical rule for describing the {{gli|electron configuration}} of atoms in certain molecules: the maximum number of {{gli|electron pair|electron pairs}} that can be accommodated in the {{gli|valence electron|valence}} {{gli|electron shell|shell}} of an element in the first row of the {{gli|periodic table}} is four (or eight total electrons). For elements in the second and subsequent rows, there are many exceptions to this rule.}}

{{term|optical activity}}

{{defn|}}

{{term|orbital}}

{{defn|may refer to either an atomic orbital or a molecular orbital}}

{{term|orbital hybridisation}}

{{defn|}}

{{term|order of reaction}}

{{defn|}}

{{term|organic acid}}

{{defn|}}

{{term|organic compound}}

{{defn|Any {{gli|compound|chemical compound}} that contains one or more {{gli|carbon}} atoms. Contrast {{gli|inorganic compound}}.}}

{{term|organic chemistry}}

{{defn|A branch of chemistry concerned with the chemical properties and reactions of {{gli|organic compound|organic compounds}}. Contrast {{gli|inorganic chemistry}}.}}

{{term|organic redox reaction}}

{{defn|}}

{{term|osmotic pressure}}

{{defn|}}

{{term|other metal}}

{{defn|Any of the {{gli|metal|metallic}} elements in the {{gli|p-block}}, which are characterized by having a combination of relatively low {{gli|melting point|melting points}} (all less than 950 K) and relatively high {{gli|electronegativity}} values (all more than 1.6, revised Pauling).}}

{{term|oxidation}}

{{defn|}}

{{term|oxidation state}}

{{ghat|Also called oxidation number.}}{{defn|no=1|The degree of {{gli|oxidation}} of an individual atom in a chemical compound, measured as the decrease in the number of {{gli|electron|electrons}} relative to the atom's naturally occurring elemental state.}}{{defn|no=2|The hypothetical {{gli|electric charge}} (positive, negative, or zero) that an atom would have if all bonds to atoms of different elements were 100% {{gli|ionic bond|ionic}}, with no {{gli|covalent bond|covalent}} component.}}

{{term|oxidizing agent}}

{{defn|}}

{{term|oxoacid}}

{{ghat|Also called an oxyacid or oxacid.}}{{defn|no=1|Any {{gli|acid}} having {{gli|oxygen}} in the acidic group.}}{{defn|no=2|Any compound which contains oxygen, at least one other element, and at least one {{gli|hydrogen}} atom bound to oxygen, and which produces a {{gli|conjugate base}} by the loss of positive hydrogen {{gli|ion|ions}}.}}

{{term|oxygen}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

P

{{glossary}}

{{term|p-block}}

{{defn|}}

{{term|pH}}

{{defn|defn=A logarithmic scale used to specify the {{gli|acid|acidity}} or {{gli|base|basicity}} of an {{gli|aqueous solution}}. The pH scale approximates the negative of the base 10 logarithm of the {{gli|molar concentration}} of {{gli|hydrogen}} {{gli|ion|ions}} in a solution. At {{gli|room temperature}}, pure water is neutral (pH = 7); solutions with a pH less than 7 are acidic and those with a pH greater than 7 are basic.}}

{{term|pascal}}

{{defn|}}

{{term|passivation}}

{{defn|}}

{{term|phase}}

{{defn|}}

{{term|phase transition}}

{{defn|no=1|A transformation of a {{gli|chemical substance}} between {{gli|solid}}, {{gli|liquid}}, and {{gli|gas|gaseous}} {{gli|state of matter|states of matter}} and, in rare cases, {{gli|plasma|plasma}}.}}{{defn|no=2|The measurable values of the external conditions at which such a transformation occurs.}}

{{term|phi bond}}

{{defn|}}

{{term|physical chemistry}}

{{defn|A branch of chemistry that studies chemical systems in terms of the principles, practices, and concepts of physics, such as motion, energy, force, time, thermodynamics, {{gli|chemical equilibrium}}, and statistical mechanics, among others. In contrast to chemical physics, physical chemistry is predominantly (though not entirely) a macroscopic science that studies the physical and chemical interactions of bulk quantities of matter.}}

{{term|pi bond}}

{{defn|}}

{{term|pipette}}

{{defn|}}

{{term|plasma}}

{{defn|One of the four fundamental {{gli|state of matter|states of matter}}, in which very high-energy particles are partially or fully {{gli|ionization|ionized}} to the point that they display unique properties and behaviors unlike those of the other three states. Plasma does not exist freely on the Earth's surface under natural conditions.}}

{{term|period}}

{{defn|A horizontal row of the {{gli|periodic table|periodic table of the elements}} and the elements that share it. Contrast {{gli|group}}.}}

{{term|periodic table of the elements}}

{{defn|A tabular arrangement of the {{gli|element|chemical elements}} organized by their {{gli|atomic number}}, {{gli|electron configuration}}, and other chemical properties, whose adopted structure shows periodic trends and is used by chemists to derive relationships between various elements as well as predict the properties and behaviors of undiscovered or newly synthesized elements. The first periodic table of the elements was published by Russian chemist Dmitri Mendeleev in 1869. Also simply called the periodic table.}}

{{term|polarity}}

{{defn|}}

{{term|potential energy}}

{{defn|The stored energy in a body or in a system due to its position in a force field or due to its configuration.}}

{{term|precipitate}}

{{defn|The formation of a {{gli|solid}} in a {{gli|solution}} or inside another solid during a chemical reaction or by diffusion in a solid.}}

{{term|precision}}

{{defn|How close the results of multiple experimental trials or observations are to each other. Compare {{gli|accuracy}}.}}

{{term|photon}}

{{defn|A carrier of {{gli|electromagnetic radiation}} of all wavelengths (such as gamma rays and radio waves).}}

{{term|polyatomic ion}}

{{defn|A {{gli|molecule}} composed of two or more {{gli|covalent bond|covalently bonded}} {{gli|atom|atoms}} which collectively bear a net {{gli|electric charge}} and therefore act as an {{gli|ion}}.}}

{{term|proton}}

{{defn|A {{gli|subatomic particle}} with a positive electric charge that is found in the {{gli|nucleus}} of an {{gli|atom}}. Often denoted with the symbol H+.}}

{{term|protonation}}

{{defn|The addition of a {{gli|proton}} (H+) to an atom, molecule, or ion.}}{{term|pure substance}}{{defn|See {{gli|chemical substance}}.}}

{{term|pyrolysis}}

{{defn|The thermal decomposition of materials at elevated temperatures in an inert atmosphere such as a vacuum gas.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

Q

{{glossary}}

{{term|quantum mechanics}}

{{defn|The study of how atoms, molecules, {{gli|subatomic particle|subatomic particles}}, etc. behave and are structured.}}

{{term|quark}}

{{defn|An elementary particle and a fundamental constituent of matter.}}

{{term|quantum}}

{{ghat|(pl.) quanta}}{{defn|The minimum amount of bundle of energy.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

R

{{glossary}}

{{term|racemate}}

{{defn|An equimolar {{gli|mixture}} of a pair of {{gli|enantiomer|enantiomers}} which does not exhibit {{gli|optical activity}}. The chemical name or formula of a racemate is distinguished from those of the enantiomers by the prefix (±)- or by the symbols RS and SR.}}

{{term|radiation}}

{{defn|Energy released in the form of waves or {{gli|subatomic particle|subatomic particles}} when there is a change from high-energy to low-energy states.}}

{{term|radioactive decay}}

{{defn|The process of an unstable atomic nucleus losing energy by emitting radiation.}}

{{term|Raoult's law}}

{{defn|}}

{{term|rare-earth metal}}

{{defn|}}

{{term|rate equation}}

{{defn|}}

{{term|rate law}}

{{defn|}}

{{term|reactant}}

{{ghat|Sometimes used interchangeably with {{gli|reagent}}.}}{{defn|Any substance that is consumed in the course of a {{gli|chemical reaction}}.}}

{{term|reaction mechanism}}

{{defn|}}

{{term|reaction rate}}

{{defn|The speed at which {{gli|reactant|reactants}} are converted into {{gli|product|products}} in a {{gli|chemical reaction}}.}}

{{term|reaction rate constant}}

{{defn|}}

{{term|reactive intermediate}}

{{defn|}}

{{term|reactivity series}}

{{defn|}}

{{term|reagent}}

{{ghat|Also another name for a {{gli|reactant}}.}}{{defn|A test substance that is added to a system in order to bring about a {{gli|chemical reaction}} or to see whether a reaction occurs.}}

{{term|redox}}

{{defn|}}

{{term|reducing agent}}

{{defn|}}

{{term|reduction potential}}

{{defn|}}

{{term|resonance}}

{{defn|}}

{{term|retort}}

{{defn|}}

{{term|rust}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

S

{{glossary}}

{{term|s-block}}

{{defn|The collective name for the elements in Groups 1 and 2 of the {{gli|periodic table}} (the {{gli|alkali metal|alkali}} and {{gli|alkaline metal|alkaline metals}}), as well as hydrogen and helium.}}

{{term|salt}}

{{defn|Any {{gli|ionic compound}} composed of one or more {{gli|anion|anions}} and one or more {{gli|cation|cations}}.}}

{{term|salt bridge}}

{{defn|A device used to connect reduction with oxidation half-cells in an {{gli|electrochemical cell}}.}}

{{term|saline solution}}

{{defn|A common term for a {{gli|solution}} of sodium chloride (NaCl) dissolved in water (H2O).}}

{{term|Schrödinger equation}}

{{defn|A quantum state equation which represents the behaviour of an election around an atom.}}

{{term|scientific theory}}

{{defn|}}

{{term|second-order reaction}}

{{defn|}}

{{term|semiconductor}}

{{defn|An electrically conductive solid whose degree of conductivity lies somewhere between that of a {{gli|conductor}} and that of an {{gli|insulator}}.}}

{{term|serial dilution}}

{{defn|}}

{{term|side chain}}

{{defn|}}

{{term|single bond}}

{{defn|A {{gli|bond}} that involves the sharing of one {{gli|electron pair|pair of electrons}}.}}{{term|skeletal formula}}{{defn|}}

{{term|sol}}

{{defn|A suspension of solid particles in liquid. Artificial examples include sol-gels.}}

{{term|solid}}

{{defn|One of the four fundamental {{gli|state of matter|states of matter}}, characterized by relatively low-energy particles packed closely together in rigid structures with definite shape and volume. See {{gli|Young's modulus|Young's modulus}}.}}

{{term|solubility}}

{{defn|The property of a {{gli|solid}}, {{gli|liquid}}, or {{gli|gas|gaseous}} {{gli|solute}} to {{gli|dissolution|dissolve}} in a solid, liquid, or gaseous {{gli|solvent}}. It is typically expressed as the proportion of solute dissolved in the solvent in a saturated solution.}}

{{term|solute}}

{{defn|The part of a {{gli|solution}} that is dissolved into the {{gli|solvent}}. For example, sodium chloride (NaCl) is the solute in a solution of saline water.}}

{{term|solution}}

{{defn|A homogeneous {{gli|mixture}} made up of multiple substances generally referred to as {{gli|solute|solutes}} and {{gli|solvent|solvents}}.}}

{{term|solvation shell}}

{{defn|}}

{{term|solvent}}

{{defn|The part of a {{gli|solution}} that dissolves the {{gli|solute}}. For example, water (H2O) is the solvent in a solution of saline water.}}

{{term|spectrochemistry}}

{{defn|}}

{{term|spectroscopy}}

{{defn|The study of {{gli|radiation}} and {{gli|matter}}, such as {{gli|X-ray}} absorption and emission spectroscopy.}}

{{term|speed of light}}

{{defn|defn=A physical constant defined as the speed of anything that has zero rest mass (Energyrest = mc², where m is the mass and c is the speed of light).}}{{term|standard solution}}{{defn|}}

{{term|standard conditions of temperature and pressure}}

{{defn|A standardisation of ambient {{gli|temperature}} and {{gli|pressure}} used in order to easily compare experimental results. Standard temperature is 25 degrees Celsius (°C) and standard pressure is 100.000 kilopascals (kPa). Standard conditions are often denoted with the abbreviation STP or STAP.}}

{{term|state of matter}}

{{defn|matter having a homogeneous, macroscopic phase; gas, plasma, liquid, and solid are the most well-known (in increasing concentration).}}

{{term|stereochemistry}}

{{defn|}}

{{term|stereoisomer}}

{{defn|An {{gli|isomer}} which possesses an identical {{gli|chemical composition}} but which differs in the spatial arrangement of its atoms.}}

{{term|stoichiometry}}

{{defn|}}

{{term|structural formula}}

{{defn|}}

{{term|structural isomer}}

{{defn|}}

{{term|subatomic particle}}

{{defn|Any particle that is smaller than an {{gli|atom}}. Examples include {{gli|proton|protons}}, {{gli|neutron|neutrons}} and {{gli|electron|electrons}}.}}

{{term|sublimation}}

{{defn|The {{gli|phase transition}} of a substance from a {{gli|solid}} to a limewater fuel or {{gli|gas}} without an apparent intervening transition to a {{gli|liquid}} in the process.}}{{term|substance}}{{defn|See {{gli|chemical substance}}.}}

{{term|substituent}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

T

{{glossary}}

{{term|talc}}

{{defn|A mineral representing the one on the Mohs Scale and composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2.}}

{{term|tarnish}}

{{defn|}}

{{term|temperature}}

{{defn|A proportional measure of the average {{gli|kinetic energy}} of the random motions of the constituent microscopic particles of a system. The {{gli|SI}} base unit for temperature is the {{gli|kelvin}}.}}

{{term|theoretical yield}}

{{defn|See {{gli|yield}}.}}

{{term|theory}}

{{defn|An experimentally testable model describing the nature of a phenomenon.}}

{{term|thermal conductivity}}

{{defn|The property of a material that allows it to conduct thermal energy or {{gli|heat}} (a quantity often denoted by ).}}

{{term|thermochemistry}}

{{defn|The study of the absorption or release of {{gli|heat}} during a {{gli|chemical reaction}}.}}

{{term|thermodynamics}}

{{defn|The study of the effects of changing temperature, volume or pressure (or work, heat, and energy) on a macroscopic scale.}}

{{term|thermodynamic stability}}

{{defn|The condition of a system being in its lowest energy state with its environment (equilibrium).}}

{{term|thermometer}}

{{defn|An instrument used to measure {{gli|temperature}}.}}

{{term|titration}}

{{ghat|Also called titrimetry or volumetric analysis.}}{{defn|A laboratory method of quantitative chemical analysis that is used to determine the {{gli|concentration}} of an identified {{gli|analyte}}. The procedure involves preparing a particular {{gli|reagent}} as a {{gli|standard solution}} of known concentration and volume (called the titrant or titrator) and allowing it to {{gli|chemical reaction|react}} with a solution of the analyte (called the titrand) to determine the latter's concentration.}}

{{term|torr}}

{{defn|A unit for measuring {{gli|pressure}} (one torr is equivalent to 133.322 Pa or 1.3158×10−3 atm).}}

{{term|transition metal}}

{{defn|An {{gli|element}} whose atoms naturally occur with incompletely filled "d" sub-shells. These elements are grouped as the so-called {{gli|d-block|d-block elements}} in the {{gli|periodic table}}.}}

{{term|transuranic element}}

{{defn|Any element with an {{gli|atomic number}} greater than 92 (i.e. occurring after uranium in the {{gli|periodic table}}). None of the transuranic elements are stable in natural conditions.}}

{{term|triple bond}}

{{defn|A {{gli|bond}} that involves the {{gli|covalent bond|covalent}} sharing of three {{gli|electron pair|pairs of electrons}} (for example, the diatomic nitrogen molecule, N2, is composed of two nitrogen atoms linked by a triple bond).}}

{{term|triple point}}

{{defn|The place where {{gli|temperature}} and {{gli|pressure}} of three phases are the same. Water has a special phase diagram.}}

{{term|Tyndall effect}}

{{defn|The effect of light scattering by {{gli|colloid|colloidal}} or suspended particles.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

U

{{glossary}}

{{term|UN number}}

{{defn|A four-digit code used to note hazardous and flammable substances.}}

{{term|uncertainty}}

{{defn|The notion that any measurement that involves estimation of any amount cannot be exactly reproducible.}}

{{term|uncertainty principle}}

{{defn|knowing the location of a particle makes the momentum uncertain, while knowing the momentum of a particle makes the location uncertain.}}

{{term|unified atomic mass unit (u)}}

{{ghat|Also called a Dalton (Da).}}{{defn|A unit of {{gli|mass}} approximately equal to the mass of one {{gli|proton}} or {{gli|neutron}}. It is sometimes equated with the technically distinct and obsolete atomic mass unit and abbreviated amu.}}

{{term|unit cell}}

{{defn|The smallest repeating unit of a crystalline {{gli|lattice}}.}}

{{term|unit factor}}

{{defn|statements used in converting between units.}}

{{term|unpaired electron}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

V

{{glossary}}

{{term|vacuum flask}}

{{ghat|Also called a Dewar flask or thermos.}}{{defn|A storage vessel consisting of two {{gli|flask|flasks}} or other containers, placed one within the other and joined at the neck, and a space in between that is partially evacuated of air, creating a near-vacuum that significantly reduces the transfer of {{gli|heat}} between the vessel's interior and its ambient environment. Vacuum flasks can greatly lengthen the time over which their contents remain warmer or cooler than the ambient environment.}}

{{term|valence electron}}

{{defn|Any of the outermost {{gli|electron|electrons}} of an atom, which are located in {{gli|electron shell|electron shells}}.}}

{{term|valence bond theory}}

{{defn|A theory explaining the chemical bonding within molecules by discussing valencies, the number of chemical bonds formed by an atom.}}

{{term|valency}}

{{defn|The combining capacity of an element.}}

{{term|van der Waals force}}

{{defn|One of the forces (attraction/repulsion) between molecules.}}

{{term|van 't Hoff factor}}

{{defn|The ratio of {{gli|mole|moles}} of particles in {{gli|solution}} to moles of {{gli|solute}} dissolved.}}

{{term|vapor}}

{{defn|When a substance is below the critical temperature while in the {{gli|gas}} phase.}}

{{term|vapor pressure}}

{{defn|The pressure of vapor over a liquid at equilibrium.}}

{{term|vaporization}}

{{ghat|Also called boiling.}}{{defn|The {{gli|phase transition}} of a substance from a {{gli|liquid}} to a {{gli|gas}}.}}

{{term|viscosity}}

{{defn|A measure of the resistance of a {{gli|liquid}} to flow.}}

{{term|volt}}

{{defn|A unit that measures the electrical potential transferred. One volt (V) is defined as one {{gli|joule}} of {{gli|mechanical work|work}} per {{gli|coulomb}}.}}

{{term|voltmeter}}

{{defn|An instrument that measures electrical cell potential.}}

{{term|volume}}

{{defn|The quantity of three-dimensional space enclosed by a closed surface, or the space that a {{gli|chemical substance|substance}} (solid, liquid, gas, or plasma) or shape occupies or contains. The {{gli|SI}} unit for volume is the cubic metre (m3).}}

{{term|volumetric analysis}}

{{defn|See titration.}}

{{term|volumetric flask}}

{{defn|}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

W

{{glossary}}

{{term|watch glass}}

{{defn|}}

{{term|water}}

{{defn|A {{gli|polar}} {{gli|inorganic compound}} with the chemical formula H2O that is a tasteless, odorless, and generally colorless {{gli|liquid}} at {{gli|standard temperature and pressure}}, though it also occurs naturally as a {{gli|solid}} and a {{gli|gas}} at the Earth's surface. It is the most abundant substance on Earth and therefore an integral component of virtually all chemical and biological systems. Water is often described as the "universal {{gli|solvent}}" for its inherent ability to {{gli|dissolution|dissolve}} many substances.}}

{{term|wave function}}

{{defn|a function describing the electron's position in a three-dimensional space.}}

{{term|work}}

{{defn|the amount of force over distance and is in terms of joules (energy).}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

X

{{glossary}}

{{term|X-ray}}

{{defn|A form of ionizing, electromagnetic radiation between gamma and UV rays in the electromagnetic spectrum.}}

{{term|X-ray diffraction}}

{{defn|a method for establishing structures of crystalline solids using single wavelength X-rays and looking at diffraction pattern.}}

{{term|X-ray photoelectron spectroscopy}}

{{defn|A {{gli|spectroscopy|spectroscopic}} technique used to measure the composition of a material.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

Y

{{glossary}}

{{term|yield}}

{{defn|The quantifiable amount of {{gli|product}} produced during a {{gli|chemical reaction}}.}}{{glossary end}}

Z

{{glossary}}

{{term|zone melting}}

{{defn|A way to remove impurities from an element by melting it and slowly travel down an ingot (cast).}}

{{term|zwitterion}}

{{defn|A chemical compound whose net charge is zero and hence is electrically neutral. But there are some positive and negative charges in it, due to the formal charge, owing to the partial charges of its constituent atoms.}}

{{term|zinc}}

{{defn|A metallic {{gli|element|chemical element}} with {{gli|atomic number}} 30 and {{gli|atomic symbol|symbol}} Zn.}}{{glossary end}}{{Compact ToC|side=yes|center=yes|top=yes|num=yes|extlinks=yes|seealso=yes|refs=yes|nobreak=yes|}}

See also

  • Chemistry
  • List of chemical elements
  • Glossary of areas of mathematics
  • Glossary of astronomy
  • Glossary of biology
  • Glossary of calculus
  • Glossary of engineering
  • Glossary of physics
  • Glossary of probability and statistics

External links

  • IUPAC Compendium of Chemical Terminology
{{wikibooks|Chemistry}}{{wikiquote|English_chemistry_mnemonics}}{{Glossaries of science and engineering}}

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