lattice enthalpy

Question 1

What can lattice enthalpy be used as a measure of?

Answer 1

Ionic bond strength.

Question 2

What 2 factors affect lattice enthalpy and enthalpy change of hydration?

Answer 2

Charge difference between ions:
○ Greater ⇒ stronger bonds ⇒ more energy released
when broken ⇒ more exothermic enthalpy Ionic radius:
○ Smaller ⇒ stronger bonds ⇒ more energy released when broken ⇒ more exothermic enthalpy

Question 3

When does a ionic substance generally dissolve?

Answer 3

If the hydration enthalpy > magnitude of lattice enthalpy so the overall enthalpy change is negative.

Question 4

What does enthalpy change of solution tell you about solubility and why?

Answer 4

The more negative/exothermic the more soluble ∵ bond making is exothermic and bonds are made when water molecules bond to ions.

Question 5

What are the key points / features of a Born-Haber cycle

Answer 5

● Downwards arrows - exothermic. Upwards arrows - endothermic.
● May have to double or triple numbers occasionally.