Energy cycles

Question 1

Lattice enthalpy

Answer 1

strength of ionic bonds

Question 2

Lattice dissociation enthalpy

Answer 2

Energy required to convert one mole of solid compound into gaseous ions

Question 3

What affects the strength of ionic bonds?

Answer 3

• Size of ions in metal - Ionic radius
• Charge density

Higher charge density=stronger ionic bond=higher lattice enthalpy

Question 4

Values needed to calculate lattice enthalpy

Answer 4

1. Enthalpy of formation
2. Enthalpy of atomisation
3. Ionisation energy
4. Electron affinity

Question 5

Enthalpy of atomisation

Answer 5

Energy required to change one mole of atoms from standard state to gaseous state

Question 6

Energy change of first electron affinity

Answer 6

Exothermic

Question 7

Energy change of second electron affinity

Answer 7

Endothermic

Question 8

In what two ways does covalent character increase?

Answer 8

1. Down a group and across a period
2. as the difference between experimental and theoretical lattice enthalpies increases

Question 9

Which ionic compounds have higher difference between experimental and theoretical lattice enthalpies?

Answer 9

Those with lower electronegative difference, which means less ionic character

Question 10

What happens when a metal ion dissolves(short)?

Answer 10

It is surrounded by opposite dipoles of the water molecules

Question 11

Process of metal ion dissolving

Answer 11

1. Ionic bonds must break
2. Then bonds in the solute break
3. New bonds form between solvent and solute