Glossary of chemistry terms

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 features an extensive vocabulary and a significant amount of jargon.

Note: All periodic table references refer to the IUPAC Style of the Periodic Table.

Also acid ionization constant or acidity constant.Also actinoids.Also paraffin.Also olefin.Also acetylene.Also enplethy, chemical amount, or simply amount.Also amphiprotic.Also proton number.Also kindling point.Also main chain.Also Rutherford–Bohr model.Also ebullition.Also Florence flask.Also vaporization point.Also simply called a buffer.Also stopper or cork.Also spelled buret.Also simply CAS Number.Also simply called a chemical.Also pure substance or simply substance.Also chromometer.Also molecular bond.Also unified atomic mass unit (u).Also drying agent.Also hydrogen-2 or heavy hydrogen, and symbolized 2H or D.Also coordinate covalent bond, coordinate bond, dative bond, and semipolar bond.Also solvation.Also malleability.Also electron magnetic moment.Also crystallization point.Also depression of freezing point.Also family.Also simply called Hess' law.Informally synonymous with proton.Also universal gas constant.Also general gas equation.Also ketoacid.Also lanthanoids.Also referred to as visible light.Also atomic mass number or nucleon number.Also liquefaction point.Also carbinyl.Also molality.Also molarity, amount concentration, or substance concentration.Also mole fraction.Sometimes used interchangeably with molecular weight and formula weight.Also inert gas.Also Lewis octet rule.Also orbital hybridization.Also osmolarity.Also oxidation number.Also oxidant, oxidizer, or electron acceptor.Also oxyacid or oxacid.Also amyl.Also simply the periodic table.Also peroxide and sometimes peroxo.Also spelled pipet.Also protogenic.(pl.)

quantaAlso free radical.Also radioisotope.Also called rare-earth metals or used interchangeably with lanthanides.Also rate law.Also rate-limiting step.Sometimes used interchangeably with reagent.Also simply intermediate.Also activity series.Also reductant, reducer, or electron donor.Also ultrasonication.Also massic heat capacity.Also stereocenter.Also spatial isomer.Also constitutional isomer.Also titrimetry or volumetric analysis.Also superheavy elements.Also transuranium elements.Also Dewar flask or thermos.Also equilibrium vapor pressure.Also boiling.Also water of hydration.Also bench chemistry or classical chemistry.Also inner salt and dipolar ion.

The skeletal formula for a generic aldehyde , where R denotes a variable carbon-containing substituent group
An atom with protons , neutrons , and electrons labelled
The skeletal formula for a generic carboxylic acid , with R denoting a variable carbon-containing substituent group
Structural diagrams of two chiral molecules, the non-superposable mirror-image enantiomers ( S )-alanine (left) and ( R )-alanine (right). Though they have identical structural formulas and the same physical properties, they are nevertheless different chemicals, and react differently with other chiral compounds.
An example of large-scale, rapid combustion
A diatomic hydrogen molecule, H
2 (right), is formed by a covalent bond when two single hydrogen atoms share two electrons between them.
A sodium ion (Na + ) forms a solvation complex with water molecules when dissolved in an aqueous solution.
The skeletal formula for a generic ester , with R and R′ denoting variable carbon-containing substituent groups
The skeletal formula for a generic ether , with R and R′ denoting variable carbon-containing substituent groups
A diagram of a laboratory apparatus designed for fractional distillation
An ionic bond between a sodium atom (Na) and a fluorine atom (F). The sodium atom loses its sole valence electron (leaving the atom with a positive electrical charge ), and the fluorine atom gains this same electron via an exothermic process (giving the atom a negative electrical charge). The oppositely charged ions are then attracted to each other to form a new compound called sodium fluoride .
The skeletal formula for a generic ketone , with R and R′ denoting variable carbon-containing substituent groups
Various ways of depicting a methyl group in structural formulae
A 1.7-milliliter microcentrifuge tube or Eppendorf tube containing Coomassie Blue solution
During osmosis , the transfer of solvent molecules out of the more dilute solution (in the left beaker, on the left side of the membrane) increases that solution's solute concentration, while the simultaneous addition of solvent to the more concentrated solution on the other side of the membrane decreases its own concentration. The eventual result is an equilibrium of the solute concentrations on both sides of the membrane, though the volumes on each side are no longer equal (right beaker).
The modern periodic table of the elements . The horizontal rows are called periods and the vertical columns are called groups or families.
This diagram shows the nomenclature commonly used for each of the different phase transitions .
The skeletal formula for a generic thiol , where R denotes a variable carbon-containing substituent group
A phase diagram showing the triple point and critical point of a substance