5.2.1 Lattice Enthalpy

• What is lattice enthalpy?

  Formation of 1 mole of ionic lattice
• What does a more exothermic lattice enthalpy indicate?

  Stronger ionic bonds
• Why can't lattice enthalpy be measured directly?

  1 mole of ionic solid can't be formed
• What is the enthalpy change of solution?

  Change when 1 mole of solute dissolves
• What is the enthalpy change of hydration?

  Change when gaseous ions dissolve in water
• What factors impact the size of lattice enthalpy?

  • Size of ions involved
  • Charges on the ions
  • Ionic bond strength
• Which ions have more negative lattice enthalpy values, smaller or larger ions?

  Smaller ions
• Why do smaller ions have more negative lattice enthalpy values?

  They can get closer, creating stronger attraction
• Describe hydration in ionic solutions.

  • Ionic lattice breaks
  • Ions become part of the solution
  • Positive ions attracted to negative oxygen
  • Negative ions attracted to positive hydrogen
• What factors impact the magnitude of the enthalpy of hydration?

  • Size of the ion
  • Charge on the ions