5.2.1 - Lattice enthalpy

Question 1

Define lattice enthalpy

Answer 1

Formation of 1 mole of ionic lattice from gaseous ions under standards conditions

Question 2

What does a more exothermic lattice enthalpy mean?

Answer 2

More exothermic = more stronger ionic bonds

Question 3

Why is it not possible to measure lattice enthalpy directly?

Answer 3

It is not possible to form 1 mole of ionic solid from its gaseous ions

Question 4

Define enthalpy change of solution

Answer 4

Enthalpy change that takes place when 1 mole of a solute is completely dissolved. in water under standard conditions

Question 5

Define enthalpy change of hydration

Answer 5

The enthalpy change that takes place when dissolving one mole of gaseous ions in water

Question 6

What are the factors that impact the size of lattice enthalpy?

Answer 6

• Size of ions involved
• Charges on the ions
• Ionic bond strength

Question 7

Which ions have more negative lattice enthalpy value? Smaller or larger ions? Why?

Answer 7

Smaller ions because they can get closer hence more stronger attraction

Question 8

Describe hydration

Answer 8

When a ionic lattice is broken the ions become part of the solution

Positive ions get attracted towards slightly negative oxygen and negative ions get attracted towards slightly positive hydrogen

Question 9

What are the factors that impact the magnitude of enthalpy of hydration

Answer 9

• size of ions
• charge of ions