AQA A Level Chemistry- Definitions
Paper 2
spectator ion - ANSWER-ion which does not take part in a reaction
ionic lattice - ANSWER-ionic solid formed with the ions held in a three-dimensional framework
coordinate bond - ANSWER-a bond containing a shared pair of electrons with both electrons supplied by
one atom
allotropes - ANSWER-different forms of the same element in the same physical state (diamond and
graphite)
electronegativity - ANSWER-the power of an atom to attract the pair of electrons in a covalent bond
induced dipole - ANSWER-a temporary dipole caused by electrons being more distributed to one side of
an atom than the other and another molecule approaching this side will have its electrons repelled
enthalpy change - ANSWER-heat energy change at constant pressure
activation energy - ANSWER-minimum amount of energy needed for reacting particles to successfully
collide
standard enthalpy value - ANSWER-the delta H values for enthalpy changes of specific reactions
measured under standard conditions
conservation of energy - ANSWER-law stating energy cannot be created or destroyed, just converted
from one form to another
, Hess' Law - ANSWER-law stating the enthalpy change for a chemical reaction is independent of the route
taken and depends only on the initial and final states
mean bond enthalpy - ANSWER-measure of energy required to break one mole of a covalent bond
measured in the gaseous state averaged across many compounds containing the bond
dynamic equilibrium - ANSWER-where you have a steady state because the rates of the forward reaction
and reverse reaction are the same
rate of reaction - ANSWER-change in concentration of a reactant or product in a given period of time
Le Chatelier's principle - ANSWER-law stating if a factor is changed which affects a system in equilibrium,
the position of equilibrium will move in a direction so as to oppose the change
hydration reaction - ANSWER-reaction where water is added is added to a compound
functional group - ANSWER-group of atoms which are responsible for the characteristic reactions of a
compound
homologous series - ANSWER-group of compounds with the same general formula
structural isomer - ANSWER-structure with the same molecular formula but different structural formula
saturated - ANSWER-each atom has the maximum number of single bonds
fractional distillation - ANSWER-continual evaporation and condensation of a mixture causing the
components to separate because of a difference in boiling point
fraction - ANSWER-group of compounds with similar boiling points and are removed at the same level of
a fractionating column
Paper 2
spectator ion - ANSWER-ion which does not take part in a reaction
ionic lattice - ANSWER-ionic solid formed with the ions held in a three-dimensional framework
coordinate bond - ANSWER-a bond containing a shared pair of electrons with both electrons supplied by
one atom
allotropes - ANSWER-different forms of the same element in the same physical state (diamond and
graphite)
electronegativity - ANSWER-the power of an atom to attract the pair of electrons in a covalent bond
induced dipole - ANSWER-a temporary dipole caused by electrons being more distributed to one side of
an atom than the other and another molecule approaching this side will have its electrons repelled
enthalpy change - ANSWER-heat energy change at constant pressure
activation energy - ANSWER-minimum amount of energy needed for reacting particles to successfully
collide
standard enthalpy value - ANSWER-the delta H values for enthalpy changes of specific reactions
measured under standard conditions
conservation of energy - ANSWER-law stating energy cannot be created or destroyed, just converted
from one form to another
, Hess' Law - ANSWER-law stating the enthalpy change for a chemical reaction is independent of the route
taken and depends only on the initial and final states
mean bond enthalpy - ANSWER-measure of energy required to break one mole of a covalent bond
measured in the gaseous state averaged across many compounds containing the bond
dynamic equilibrium - ANSWER-where you have a steady state because the rates of the forward reaction
and reverse reaction are the same
rate of reaction - ANSWER-change in concentration of a reactant or product in a given period of time
Le Chatelier's principle - ANSWER-law stating if a factor is changed which affects a system in equilibrium,
the position of equilibrium will move in a direction so as to oppose the change
hydration reaction - ANSWER-reaction where water is added is added to a compound
functional group - ANSWER-group of atoms which are responsible for the characteristic reactions of a
compound
homologous series - ANSWER-group of compounds with the same general formula
structural isomer - ANSWER-structure with the same molecular formula but different structural formula
saturated - ANSWER-each atom has the maximum number of single bonds
fractional distillation - ANSWER-continual evaporation and condensation of a mixture causing the
components to separate because of a difference in boiling point
fraction - ANSWER-group of compounds with similar boiling points and are removed at the same level of
a fractionating column
