Lattice enthalpy PMT flashcards

• What is lattice enthalpy?

  Energy change when forming ionic lattice
• What does the formation of 1 mole of ionic lattice involve?

  Gaseous ions under standard conditions
• 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 ions
• Why do smaller ions have more negative lattice enthalpy values?

  They can get closer, creating stronger attraction
• What factors impact the magnitude of the enthalpy of hydration?

  • Size of the ion
  • Charge on the ions
• What is hydration in the context of ionic compounds?

  • Ionic lattice breaks
  • Ions become part of the solution
  • Positive ions attracted to negative oxygen
  • Negative ions attracted to positive hydrogen
• How to predict solubility ?

  If the sum of the hydration enthalpies is larger than the magnitude of the lattice enthalpy, then the overall enthalpy change (enthalpy change of solution) will be exothermic and the compound should dissolve