Thermodynamics: Born-Haber Cycles, Enthalpies of Solution

Question 1

Define the term enthalpy of solution

Answer 1

• ∆Ηsol°

- Enthalpy change when one mole of a solid ionic compound is dissolved in water to produce aqueous ions

Question 2

Define the term enthalpy of hydration

Answer 2

• ∆Ηhyd°

- Enthalpy change when one mole of gaseous ions is converted to one mole of aqueous ions

Question 3

Define the term lattice enthalpy of dissociation

Answer 3

• ∆ΗLDE°

- Enthalpy change when one mole of a solid ionic compound is dissociated into its gaseous ions

Question 4

Draw an enthalpy cycle for calculating the enthalpy change of solution

Answer 4

Question 5

Write an equation to calculate the enthalpy change of solution

Answer 5

• ∆Ηsol° = ∆ΗLDE° + ∆Ηhyd°

Question 6

What occurs when ions are present in water?

Answer 6

• Oppositely charged, Hδ+ or OHδ-, ions form permanent dipole forces with ions
• Hydrogen bonds may form between Hδ+ and lone pair on N, O or F δ- ion