Chemistry Definitions F321 F322

the mass of an atom of an isotope compared with one twelfth of the mass of carbon-12.

the weighted mean mass of an atom of an element when compared with one twelfth of the mass of a carbon-12 atom.

the weighted mean mass of a molecule compared with one twelfth of the mass of the atm carbon-12.

the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope.

the mass per mole of a substance.

the simplest whole number ratio of atoms of each element present in a compound.

the amount of solute dissolved in a solution per 1dm3.

a species that is a proton donor.

a species that is a proton accepter.

a type of base that dissolves in water forming hydroxide iona (OH-).

any chemical compound formed from an acid when a H+ ion has been replaced by a metal ion or another positive ion.

water molecules that form an essential part of the crystaline structure of a compound.

a measure of the number of electrons that an atom uses to bond with atoms of another element.

a loss of electrons or an increase in oxidation numer.

gain of electrons or a decrease in oxidation number.

a region of space within an atom that can hold up to two electrons, with opposite spins.

a measure of the attraction of a bonded atom for the pair of electrons in a covalent bond.

a regular periodic variation of properaties of elements with atomic number and position in the Periodic Table.

the breaking up of a chemical substance with heat in at least two chemical substances.

a reaction in which a more reactive element displaces a less reactive element from an aqueous solution of the latter's ions.

an organic compound which only contains hydrogen and carbon.

the part of the organic molecule which is responsible for its chemical reactions.

the simplest algebraic formula of a member of a homologous series.

molecules with the same molecular formula but with different structural arrangements of atoms.

compounds with the same structural formula, but with different arrangements of atoms in space.

a species with an unpaired electron.

the breaking of a covalent bond, with one of the bonded electrons going to each atom, forming two radicals.

the breaking of a covalent bond with both of the bonded electrons going to one of the atoms forming a cation and an anion.

an atom that is attracted to an electron-deficient centre or atom, where it donates a pair of electrons to form a new covalent bond.

an atom that is attracted to an electron-rich centre or atom, where it accepts a pair of electrons to form a new covalent bond.

the breaking down of long-chained saturated hydrocarbons to form a mixture of shorter-chained alkanes and alkenes.

the reactive part of a double bond formed above and below the plane of the bonded atoms by sideways overlap of p orbitals.

the reaction of an alcohol with a carboxylic acid to produce an ester and water.

a reaction with water or aqueous hydroxide ions that breaks a chemical compound into two compounds.

actual amount of product / desired amount of product x 100 =                                    (mols)

molecular mass of desired product / molecular mass of all products x 100

the process in mass spectrometry that causes a positive ion to split into pieces.

refers to a reaction where the enthalpy of the products is smaller than the enthalpy of the reactants, resulting in heat loss to the surroundings.

refers to a reaction where the enthalpy of the products is greater than the enthalpy of the reactants, resulting in heat being taken in from the surroundings.

the minimum energy required to start a reaction by the breaking of bonds.

the enthalpy change that takes place when one mole of a compound is formed from it's elements in their standard states under standard conditions.