Measuring Energy Changes in the Lab Enthalpies of Solution Calorimetry can be used to find the energy change in chemical reactions. This is much easier to carry out in aqueous solutions We can take...
Dissolution Energy Cycles How are enthalpy of solution and hydration enthalpies related? The relationship between lattice enthalpy, hydration enthalpies and enthalpy of solution From the diagram we...
Born-Haber Cycle Calculations Once a Born-Haber cycle has been constructed, it is possible to calculate the lattice energy (ΔHlatꝋ) by applying Hess’s law and rearranging: ΔHfꝋ = ΔHatꝋ + ΔHatꝋ + IE...
Constructing Born-Haber Cycles A Born-Haber cycle is a specific application of Hess's Law for ionic compounds and enables us to calculate lattice enthalpy, which cannot be found by experiment The b...
Key Enthalpy Terms Ionisation energy The ionisation energy (ΔHIEꝋ) is the standard enthalpy change that occurs on the removal of 1 mole of electrons from 1 mole of gaseous atoms or positively charg...
Hybrid Orbitals Hybridisation The ground state of the electrons in a carbon atom is 1s22s22p2 This can be represented using a spin diagram as shown: Orbital spin diagram for carbon in the ground st...
Ozone Revisited We have seen previously that ozone is a molecule with two resonance structures leading to a resonance hybrid The two Lewis resonance structures for ozone The central oxygen atom has...
Delocalisation & Resonance The delocalisation of electrons can explain the structures of some species that don’t seem to fit with a Lewis structure Delocalised electrons are electrons in a mole...
Formal Charge A limitation of the model of covalent bonding is that when drawing Lewis structures for molecules, it is sometimes possible to come up with more than one structure while still obeying...
