Enthalpy and Entropy (OCR A-Level Chemistry A): Flashcards
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Practise the cards
10 cards from this deck
Lattice enthalpy definition
Lattice enthalpy definition
Enthalpy change when 1 mol ionic compound separates to gaseous ions
Hydration enthalpy definition
Hydration enthalpy definition
Enthalpy change when 1 mol gaseous ions dissolve & hydrate in water
Effect of larger ions on lattice enthalpy
Effect of larger ions on lattice enthalpy
Less negative (weaker attraction, ions further apart)
Effect of higher charge on lattice enthalpy
Effect of higher charge on lattice enthalpy
More negative (stronger electrostatic attraction)
Effect of larger ions on hydration enthalpy
Effect of larger ions on hydration enthalpy
Less negative (lower charge density, weaker attraction)
Effect of higher charge on hydration enthalpy
Effect of higher charge on hydration enthalpy
More negative (stronger ion-dipole interactions)
Lattice enthalpy & melting point relationship
Lattice enthalpy & melting point relationship
More negative lattice enthalpy → higher melting point
Charge density in larger ions
Charge density in larger ions
Lower (charge spread over greater volume)
When should an ionic compound dissolve?
When should an ionic compound dissolve?
When total hydration enthalpy > lattice enthalpy (in magnitude)
Role of entropy in solubility
Role of entropy in solubility
Explains why some endothermic dissolutions still occur