Chemistry Key Definitions F322 Flashcards
HOMOLOGOUS SERIES
A series of organic compounds having the same functional group but with each successive member differing by CH2.
HYDROCARBON
A compound of hydrogen and carbon only.
SATURATED
Containing single bonds only.
UNSATURATED
Containing at least one carbon to carbon multiple bond.
EMPIRICAL FORMULA
The simplest whole number ratio of atoms of each element present in a compound.
MOLECULAR FORMULA
The actual number of atoms of each element in a molecule.
EXOTHERMIC
Heat is given out to the surroundings (the reactants lose energy).
ENDOTHERMIC
Heat is taken in from the surroundings (the reactants gain energy).
ACTIVATION ENERGY
The minimum energy required to start a reaction by the breaking of bonds.
STANDARD CONDITIONS
A pressure of 100kPa (1 atmosphere), a stated temperature, usually 298K (25oC) and a concentration of 1.0moldm-3 (for reactions with aqueous solutions).
(STANDARD) ENTHALPY CHANGE OF REACTION
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation (under standard conditions, all reactants and products being in their standard states).
(STANDARD) ENTHALPY CHANGE OF FORMATION
The enthalpy change that takes place when one mole of a compound is formed from its constituent elements (in their standard states under standard conditions).
(STANDARD) ENTHALPY CHANGE OF COMBUSTION
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen (under standard conditions, all reactants and products being in their standard states).
AVERAGE BOND ENTHALPY
The average enthalpy change that takes place when breaking,
by homolytic fission, 1 mol of a given type of bond in the molecules of a gaseous species.
FUNCTIONAL GROUP
A group of atoms responsible for the characteristic reactions of a
compound
STRUCTURAL ISOMERS
Compounds with the same molecular formula but with a different structural formulae
FRACTIONAL DISTILLATION
Separation of a liquid mixture into fractions with different boiling points.
CATALYTIC CRACKING
The breaking down of long chained saturated hydrocarbons to form
more useful alkanes (shorter chained) and alkenes.
BIOFUEL
A fuel that is derived from recently living material such as plants or from the waste of animals.
‘CURLY ARROW’
The movement of an electron pair, showing either the breaking or formation of a covalent bond.
RADICAL
A species with an unpaired electron.
HOMOLYTIC FISSION
The breaking of a covalent bond where the shared pair of electrons are
split equally, forming two radicals.
HETEROLYTIC FISSION
The breaking of a covalent bond where the shared pair electrons are
not split equally, forming a cation and an anion.
NUCLEOPHILE
A species attracted to an electron deficient centre where it donates a pair of electrons to form a new covalent bond.
