Enthalpy of Born-Haber Cycles - Thermodynamics Pt B (3.3)

Question 1

Describe what happens in the enthalpy of formation of the ionic compound NaCl

Answer 1

• 1/2 a mole of Cl2 bond is broken
• 1 mole of electrons is removed from Na
• one mole of electrons is given to Cl
• a formation of 1 mole of ionic bonds between Na+ & Cl-

(Equation: Na(s) + 1/2 Cl2(g) -> NaCl(s)

Question 2

What is first ionisation enthalpy?

Answer 2

• enthalpy change when 1 mole of gaseous atoms forms 1 mole of gaseous cations & 1 mole of electrons

Question 3

What is electron affinity?

Answer 3

• enthalpy change when 1 mole of gaseous atoms gains 1 mole of electrons to form 1 mole of gaseous anions

Question 4

What enthalpy change occurs when 1 mole of gaseous ions are formed from its elements under standard conditions?

Answer 4

Enthalpy of Atomisation

Question 5

What enthalpy change occurs when gaseous cations & anions are made into an ionic solid in its standard states?

Answer 5

Lattice Enthalpy

Question 6

Do we have to draw Born Haber cycles?

Answer 6

No - just be able to calculate values using it