Born harbour cycle

Question 1

Define lattice enthalpy

Answer 1

The enthalpy change when one mol of a solid ionic compound is broken down into gaseous ions under standard conditions

Question 2

Define bond dissociation enthalpy

Answer 2

The enthalpy change when one mole of bonds is broken in the gaseous state

Question 3

Define enthalpy of sublimation

Answer 3

The enthalpy change when one mole of solid is directly converted into a gas at constant temperature and pressure

Question 4

Define enthalpy of atomisation

Answer 4

The amount of enthalpy change when a compounds bonds are broken and the component atoms are separated into single atoms

Question 5

Define first ionisation energy

Answer 5

The enthalpy change when 1 mole of gaseous atoms each gain 1 electron

Question 6

Define second ionisation energy

Answer 6

The energy required to remove the outermost or least bound electrons from a 1+ ion of the elements

Question 7

Define first electron affinity

Answer 7

The enthalpy change when 1 mole of gaseous atoms each gain 1 electron

Question 8

In the born harbour cycle which arrows go downwards

Answer 8

Enthalpy of formation
First electron affinity
Lattice enthalpy of formation

Question 9

What does a downwards arrow on a born harbour cycle mean

Answer 9

Downward arrows show negative values therefore and exothermic process

Question 10

What do upwards arrows show on a born harbour cycle

Answer 10

Upward arrows show positive values therefore endothermic process

Question 11

What are the orders when trying to construct a born harbour cycle

Answer 11

Step 1 - enthalpy of formation - downwards arrow
Step 2- enthalpy of atomisation for the metal
Step 3 - enthalpy of atomisation for the nonmetal
Step 4 - first ionisation energy of the metal
Step 5 - second ionisation energy of the metal if required
Step 6 - electron affinity of the non metal - downwards arrow
Step 7 - second electron affinity of the non metal- upwards arrow
Step 8- lattice enthalpy of formation - downwards arrow