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Born-Haber Cycles

Physical

A2

Born-Haber

AQA Content

Define each of the above terms and lattice enthalpy
Construct Born–Haber cycles to calculate lattice enthalpies using these enthalpy changes
Construct Born–Haber cycles to calculate one of the other enthalpy changes
Compare lattice enthalpies from Born–Haber cycles with those from calculations based on a perfect ionic model to provide evidence for covalent character in ionic compounds.
Cycles are used to calculate enthalpies of solution for ionic compounds from lattice enthalpies and enthalpies of hydration.
define the term enthalpy of hydration
Perform calculations of an enthalpy change using these cycles.

Specification Notes

Lattice enthalpy can be defined as either enthalpy of lattice dissociation or enthalpy of lattice formation.

Born–Haber cycles are used to calculate lattice enthalpies using the following data:
enthalpy of formation
ionisation energy
enthalpy of atomisation
bond enthalpy
electron affinity.

Notes


Links

Definitions: Enthalpy changes
www.sciteachonline.com
Definitions: Enthalpy changes
For the following, let AB represent a compound * ‘The energy change when…’ Lattice Enthalpy *… 1 mole of an ionic compound is formed from its gaseous ions under STP (298K, 100kPa). Always exothermic Standard Enthalpy Change of Formation *… 1 mole of compound is formed from its constituent elements in their standard state. Usually exothermic. Standard Enthalpy Change of Atomisation *… 1 mole of gaseous atoms are formed from the element in its standard state. Always endothermic (bonds are broken)



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