Born Harbour Cycles

Question 1

Lattice enthalpy

Answer 1

Dissociation: enthalpy change when one mole of ionic compound is seperated into component gaseous ions (positive)
Formation: enthalpy change when one mole of an ionic compound from its constituent gaseous ions (negative)

Question 2

Enthalpy of formation

Answer 2

Enthalpy change when one mole of a compound is formed from its elements in standard states under standard conditions

Question 3

Enthalpy of atomisation

Answer 3

Enthalpy change when one mole of gaseous atoms from elements in standard states
0.5Br2 -> Br

Question 4

Bond dissociation enthalpy

Answer 4

One mole of a covalent bond is broken under standard conditions in gaseous state (positive)
Mean as averaged across many compounds containing the bind

Question 5

Ionisation energies

Answer 5

1st enthalpy change when one mole of electrons removed from one mole of gaseous atoms to form one mole of gaseous ions
2nd enthalpy change when one mole of electrons is removed from a +1 gaseous ion to form one mole of a 2+ gaseous ion

Question 6

Electron affinity

Answer 6

Enthalpy change when one mole of gaseous atoms form one mole of negative ions

Question 7

What effects the lattice enthalpy values

Answer 7

Ion sizes: smaller ions pack closer together so more attracted to each other
Ion charge: higher charges are more attracted to each other

Question 8

Perfect ionic model

Answer 8

Bonding is 100%
Ions are point charges, perfect spheres
In reality: a small large charge cation can distort a large anion so ions are distorted and not spherical
If experimental values are different to calculated there is some covalent character, forces attraction are greater
Greater the difference the greater the covalent character

Question 9

Enthalpy of solution

Answer 9

Enthalpy of lattice dissociation + enthalpy of hydration
Enthalpy change when one mole of solute dissolves in water

Question 10

Enthalpy of hydration

Answer 10

Enthalpy change when one mole of gaseous ions is converted into one mole of aqueous ions