enthalpy change

enthalpy change

measuring heat change under constant pressure

standard enthalpy of atomisation + example

is the enthalpy change which accompanies the formation of one mole of gaseous atoms from the element in its standard states and conditions

1/2Br2(l) → Br (g)

Mg(s) → Mg(g)

The first electron affinity + example

is the standard enthalpy change when a mole of gaseous atoms is converted to a mole of gaseous ions with a single negative charge

O(g) + e- → O2(g)

second electron affinity

is the enthalpy change when a mole of electrons is added to a mole of gaseous ions each with a single negative charge to form ions with two negative charges

Lattice enthalpy of formation + example

is the standard enthalpy change when one mole of solid ionic compound is formed from its gaseous ions

enthalpy of hydration + examples

is the standard enthalpy change when water molecules surround one mole of gaseous ions

Na+ (g) + aq → Na+(aq)

enthalpy of solution + example

is the standard enthalpy change when one mole of solute dissolves completely in sufficient solvent to form a solution in which molecules or ions are far apart to not interact

NaCl (s) + aq → Na+(aq) + Cl- (aq)

mean bond enthalpy

is the enthalpy change needed to break a covalent bond into gaseous atoms averaged over a range of different molecules

Order for born haber cycle

• enthalpy of atomisation (gaseous)

• ionisation

• electron affinity

• Lattice formation enthalpy

hess law

the enthalpy change of a reaction is independent of the route taken

the sum of the first five stages is equal to the

Enthalpy of formation of - -

Enthalpy of lattice dissociation + examples

is the standard enthalpy change when one mole of solid ionic compound is dissociated into its gaseous ions