Calculating Standard Entropy Change The standard molar enthalpy values, Sꝋ, relate to standard conditions of temperature and pressure The entropy change, ΔSꝋ, can be calculated from thermodynamic d...
Entropy Entropy You may have wondered why it is that endothermic reactions occur at all, after all, what can be the driving force behind endothermic reactions if the products end up in a less stabl...
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...
