Lattice Enthalpy

Question 0

The sign for lattice enthalpy is always…

Answer 0

Negative

Question 1

Define lattice enthalpy

Answer 1

The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions

Question 2

Lattice enthalpy is a measure of…

Answer 2

Ionic bond strength

Question 3

Define enthalpy change of atomisation

Answer 3

The enthalpy change that takes place when one mole of gaseous atoms forms form one mole of the element in its standard state

Question 4

Define first ionisation energy

Answer 4

The enthalpy change accompanying the removal of one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 5

Define second ionisation energy

Answer 5

The enthalpy change accompanying the removal of one electron from each ion in a group of gaseous 1+ ions to form one mole of gaseous 2+ ions

Question 6

Define first electron affinity

Answer 6

The enthalpy change accompanying the addition of one electron to each atom in a group of gaseous atoms to form one mole of gaseous 1- ions

Question 7

Define second electron affinity

Answer 7

The enthalpy change accompanying the addition of one electron to each ion in one mole of gaseous 1- ions to form one mole of gaseous 2- ions

Question 8

Define Hess’ law

Answer 8

If a reaction can take place by more than one route and the initial and final conditions are the same, the total enthalpy change is the same for each route

Question 9

Define standard enthalpy change of formation

Answer 9

The enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard States under standard conditions

Question 10

Define enthalpy change of solution

Answer 10

The enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions

Question 11

Define enthalpy change of hydration

Answer 11

The enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions under standard conditions

Question 12

Explain the effect of charge density on lattice enthalpy

Answer 12

Ions with higher charge densities will attract each other more strongly
This results in a more exothermic lattice enthalpy

Question 13

What factors affect charge density and which is more important?

Answer 13

Smaller ions with higher charges have higher charge densities
Charge always outweighs size

Question 14

What is the affect of charge density of enthalpy change of hydration?

Answer 14

Ions with higher charge densities will attract water more strongly
More water molecules are attracted so more ion-dipole intermolecular forces form, releasing more energy, resulting in a more exothermic enthalpy change of hydration