AQA A2 Chemistry: Unit 5
Thermodynamics…read more

Definitions
· Enthalpy change when one mole of compound is
Standard Molar Enthalpy formed from its constituent elements under
Change of Formation: standard conditions and all produces and
reactants in their standard states
· Enthalpy change which accompanies the
Standard Molar Enthalpy formation of one mole of gaseous atoms from the
of Atomisation: element in its standard state under standard
conditions
· Standard enthalpy change when one mole of
First Ionisation Energy: gaseous atom is converted into a mole of gaseous
ions each with a single positive charge
· Standard enthalpy change when one mole of
First Electron Affinity: gaseous atoms is converted to a mole of gaseous
ions each with a single negative charge
· Standard enthalpy change when one mole of
Second Electron Affinity: electrons is added to a mole of gaseous ions each
with a single negative charge to form ions with
two negative charges…read more

Lattice Formation · Standard enthalpy change when one mole of
solid ionic compound is formed from its gaseous
Enthalpy: ions
Enthalpy of Lattice · When one mole of ionic compound separates
Dissociation: into its gaseous ions
Enthalpy of Hydration: · Standard enthalpy change when water
molecules surround one mole of gaseous ions
· Standard enthalpy change when one mole of
solute dissolves completely in sufficient solvent
Enthalpy of Solution: to form a solution in which the molecules or
ions are far enough apart to not interact with
each other
· Enthalpy change when one mole of gaseous
Mean Bond Enthalpy: molecule breaks a covalent bond to form two
gaseous free radicals, averaged over a range of
compounds…read more

Ionic Bonding
· Electrons transferred from metal atoms to
non metal atoms
· Positively charged metal ions and negatively
charged non-metal ions are formed
· The ions arrange themselves in a lattice so
oppositely charged are next to each other…read more

Hess's Law
· Total energy change for a chemical reaction is
the same whatever route taken
· As long as the initial and final conditions are
the same…read more

Born-Haber Cycles
Rules:
· Make a rough scale
· Plan your cycle
· Remember to but in the signs of each
enthalpy change and an arrow of direction…read more