AQA A-level Chemistry Paper 1 With Questions And Answers…..
1. Explain what is meant by the term co-ordinate bond: a covalent bond in which both
electrons are donated by one atom
2. Define the term Ligand: Atom, ion or molecule which can donate a pair of electrons to a metal ion
3. What can lattice enthalpy defined as? (2 things): Lattice enthalpy of formation and lattice
enthalpy of dissociation
4. 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
5. 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
6. What 2 things might cause a different lattice enthalpy?: Enthalpy of bond dissociation (eg
halogens)
Enthalpy of formation
7. why is the lattice enthalpy greater for ions with a high charge?: There is a stronger
attraction
8. Why is the lattice enthalpy greater for smaller ions?: smaller ions are more closely packed in the
lattice
there is a stronger attraction
9. what is the relationship between enthalpy of lattice dissociation and en-
thalpy of lattice formation?: same numerical value but different signs
10. State Hess' law: Enthalpy change for any chemical reaction is independent of the route taken, and
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1. Explain what is meant by the term co-ordinate bond: a covalent bond in which both
electrons are donated by one atom
2. Define the term Ligand: Atom, ion or molecule which can donate a pair of electrons to a metal ion
3. What can lattice enthalpy defined as? (2 things): Lattice enthalpy of formation and lattice
enthalpy of dissociation
4. 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
5. 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
6. What 2 things might cause a different lattice enthalpy?: Enthalpy of bond dissociation (eg
halogens)
Enthalpy of formation
7. why is the lattice enthalpy greater for ions with a high charge?: There is a stronger
attraction
8. Why is the lattice enthalpy greater for smaller ions?: smaller ions are more closely packed in the
lattice
there is a stronger attraction
9. what is the relationship between enthalpy of lattice dissociation and en-
thalpy of lattice formation?: same numerical value but different signs
10. State Hess' law: Enthalpy change for any chemical reaction is independent of the route taken, and
1/4
