AS 2 - Definitions Flashcards
Structural Formula
shows the minimal detail for the arrangement of atoms in a molecule
Displayed Formula
shows the relative positioning of all the atoms in a molecule and the bonds between them
General Formula
shows the simplest algebraic formula of a member of a homologous series
Skeletal Formula
shows simplified organic formula by removing hydrogen atoms from alkyl chains, leaving just the carbon chain and functional groups
Homologous Series
series of organic compounds which have the same functional group, general formula and similar chemical properties, but with each successive member differing by a CH2 unit
Stereoisomers
compounds with the same molecular and structural formula, but have their atoms arranged differently in space
(Structural) Isomers
compounds with the same molecular formula, but have a different structural formula (atoms arranged differently)
Curly Arrows
represent the movement of an electron pair
Homolytic Fission
the breaking of a covalent bond, where one of the bonded electrons goes to each atom, forming two free radicals
Heterolytic Fission
the breaking of a covalent bond, with both of the bonded electrons going to one of the atoms, forming negative and positive ions
Hydrocarbon
compound containing carbon and hydrogen only
Fractional Distillation
separation of a mixture according to differences in boiling points
Biofuel
a fuel that can be obtained from plants or animals
Pi Bond
bond formed from the sideways overlap of adjacent p orbitals
Sigma Bond
single covalent bond made up of two shared electrons
Biodegradable (non)
material (that cannot be) broken down naturally by bacteria in the environment
Reflux
continuous evaporation and condensation, without loss of vapours
Standard Enthalpy of Formation
enthalpy change when one mole of a compound is formed from its elements, in their standard state, under standard conditions
Standard Enthalpy of Reaction
enthalpy change when the number of moles of reactants, as shown in the equation, react together under standard conditions
Standard Enthalpy of Combustion
enthalpy change when one mole of an element/compound reacts completely with oxygen, under standard conditions
Average Bond Enthalpy
average enthalpy change on breaking one mole of a covalent bond in a gaseous molecule, under standard conditions
Hess’s Law
the total enthalpy change for a chemical reaction is independent of the route by which the change takes place, provided the initial and final conditions are the same
Rate
the change in concentration of a reactant or product in a given time
Activation Energy
the minimum energy needed for a reaction to occur
Catalyst
a substance that increases the rate of reaction without being used up. It provides an alternative route, with a lower activation energy
Dynamic Equilibrium
A system where forward and reverse reactions proceed at identical rates
Le Chateliers Principle
When a system in equilibrium is subjected to a change, the position of equilibrium will shift to minimise that change
Greenhouse effect
process by which the absorption and subsequent emission of infrared radiation by atmospheric gases warms the lower atmosphere and the planet’s surface
Ozone Depletion Potential
relative amount of breakdown of the ozone layer caused by a particular substance
