AS Definitions Flashcards
Relative atomic mass
The mass of an atom compared to 1/12th the mass of carbon-12 atom
Orbital
A region of space around the nucleus that can hold up to two electrons with opposite spin
Electronegativity
The ability of an atom to attract a pair of electrons in a covalent bond
1st ionisation energy
The energy required to remove one electron from each atom in 1 mole of gaseous atoms
Activation energy
The minimum amount of energy particles need to react
Enthalpy of combustion
The energy change when 1 mole of a substance is completely combusted under standard conditions
Enthalpy of formation
The energy change when 1 mole of compound is made from its elements in their standard state under standard conditions
What are standard conditions?
298K
100kPa
Enthalpy of neutralisation
The energy change when an acid and base react together per mole of H2O produced
Homogeneous catalyst
A catalyst that is in the same state as the reactants
Heterogeneous catalyst
A catalyst that is in a different state to the reactants
Dynamic equilibrium
A reversible reaction where the forward and backward reaction rates are equal and therefore the concentrations of reactants and products are constant. In a closed system
Empirical formula
The simplest whole number ratio of the types of atom in a compound
Molecular formula
The exact number of each type of atom in a compound
Homologous series
A group of organic molecules with the same functional group but successive members differ by CH2 (same general formula)
Saturated
Contains only carbon-carbon single bonds
Unsaturated
Contains some multiple carbon-carbon bonds such as double or triple
Functional group
The atoms within a molecule that are responsible for the way it reacts
Aromatic
A compound containing a benzene ring
Aliphatic
A molecule with no aromatic ring (i.e. straight/branched/non-aromatic rings)
Alicyclic
An aliphatic compound with a non-aromatic ring
Homolytic fission
Bond breaking where each atom gains one of the electrons from the covalent bond - forms two radicals
Hetrolytic fission
Bond breaking where one atom gains both the electrons from the covalent bond - forms one +ve ion and one -ve
Radical
A species with an unpaired electron
Structural isomer
Compounds with the same molecular formula but a different structural formula
Steroisomer
Compounds with the same molecular formula but a different arrangement of atoms in space
Electrophile
Lone pair acceptor
Nucleophile
Lone pair donor
