AQA A-level Chemistry Paper 1 questions
and answers
Explain what is meant by the term co-ordinate bond - a covalent bond in which
both electrons are donated by one atom
Define the term Ligand - Atom, ion or molecule which can donate a pair of
electrons to a metal ion
What can lattice enthalpy defined as? (2 things) - Lattice enthalpy of formation
and lattice enthalpy of dissociation
Why is the experimental value for lattice dissociation of some compounds greater
than the theoretical value? - the bonding is not 100% ionic/ there is some
covalent character/ there is additional covalent bonding
what does the perfect ionic model assume? - The bonding in the compound is not
100% ionic. In the model the ions are perfect spheres/point charges are not
distorted
What 2 things might cause a different lattice enthalpy? - Enthalpy of bond
dissociation (eg halogens)
Enthalpy of formation
, AQA A-level Chemistry Paper 1 questions
and answers
why is the lattice enthalpy greater for ions with a high charge? - There is a
stronger attraction
Why is the lattice enthalpy greater for smaller ions? - smaller ions are more closely
packed in the lattice
there is a stronger attraction
what is the relationship between enthalpy of lattice dissociation and enthalpy of
lattice formation? - same numerical value but different signs
State Hess' law - Enthalpy change for any chemical reaction is independent of the
route taken, and depends only on the initial and final states.
Why is the second electron affinity endothermic? - Repulsion of the negative ion
with the negative electron being added
Define enthalpy of hydration - The enthalpy change when 1 mole of gaseous ions
is converted to one mole of aqueous ions
and answers
Explain what is meant by the term co-ordinate bond - a covalent bond in which
both electrons are donated by one atom
Define the term Ligand - Atom, ion or molecule which can donate a pair of
electrons to a metal ion
What can lattice enthalpy defined as? (2 things) - Lattice enthalpy of formation
and lattice enthalpy of dissociation
Why is the experimental value for lattice dissociation of some compounds greater
than the theoretical value? - the bonding is not 100% ionic/ there is some
covalent character/ there is additional covalent bonding
what does the perfect ionic model assume? - The bonding in the compound is not
100% ionic. In the model the ions are perfect spheres/point charges are not
distorted
What 2 things might cause a different lattice enthalpy? - Enthalpy of bond
dissociation (eg halogens)
Enthalpy of formation
, AQA A-level Chemistry Paper 1 questions
and answers
why is the lattice enthalpy greater for ions with a high charge? - There is a
stronger attraction
Why is the lattice enthalpy greater for smaller ions? - smaller ions are more closely
packed in the lattice
there is a stronger attraction
what is the relationship between enthalpy of lattice dissociation and enthalpy of
lattice formation? - same numerical value but different signs
State Hess' law - Enthalpy change for any chemical reaction is independent of the
route taken, and depends only on the initial and final states.
Why is the second electron affinity endothermic? - Repulsion of the negative ion
with the negative electron being added
Define enthalpy of hydration - The enthalpy change when 1 mole of gaseous ions
is converted to one mole of aqueous ions
