Enthalpy Flashcards
0
Q
Explain why it is difficult to predict whether lattice enthalpy of Magnesium sulfide would be more or less exothermic than sodium oxide.
A
- Magnesium2+ ion has a greater ionic charge and smaller ionic radius than Na+ .
- Sulphide2- ion has larger ionic radius than O2-
- Mg2+ has stronger attraction, S2- has weaker attraction
1
Q
Define the term lattice enthalpy
A
Enthalpy change accompanying the formation of 1 mole of an ionic compound from its gaseous ions under standard conditions, 298K, 1moldm-3, 1atm
2
Q
Why is enthalpy change of hydration of chloride ions exothermic?
A
Hydration involves bond forming .
Chloride ions attract water molecules.
3
Q
Why is the enthalpy change of hydration of Magnesium ions more exothermic than the enthalpy change of hydration of Calcium ions?
A
Mg2+ has a smaller ionic radius
Mg2+ has a stronger attraction to water molecules.
