Thermodynamics Flashcards
Enthalpy change
Heat energy change at constant pressure
Lattice enthalpy of Formation
Enthalpy change when one mole of a solid ionic compound is formed from its gaseous ions
Ionisation Energy
Enthalpy change when one mole of gaseous atoms is converted to gaseous ions with a positive charge
Enthalpy of Atomisation
Enthalpy change when one mole of gaseous atoms is formed from its element under standard conditions
Bond enthalpy
Enthalpy change when one mole of gaseous atoms break a covalent bond forming 2 free radicals
Electron Affinity
One mole of gaseous atoms are converted to gaseous ions with a negative charge
Lattice Enthalpy
Energy required to form one mole of solid ionic lattice from gaseous ions under standard conditions
Enthalpy of Hydration
One mole of aqueous ions formed from one mole of gaseous ions
Why might the experimental value of lattice enthalpy be different?
Most ionic compounds have covalent character
Entropy
Measure of disorder of particles
Entropy Change
∆S= S (products) - S (reactants)
Standard Entropy (S°)
Entropy of one mole of a substance under standard conditions. (100kPa) (298K)
Free energy change
∆G = ∆H – T∆S
T =
∆H / ∆S
