Enthaplies A2 Flashcards
Def of enthalpy of formation
Enthalpy change when 1 mol of a substance is formed from its elements with all substances in their standard states
Symbol and example of enthalpy of formation
(Use sodium chloride)
ΔfH⦵
E.g Na (s) + 1/2Cl2 (g) —> NaCl (s)
Def of the first ionisation enthalpy
Enthalpy change when 1 mol of electrons is removed from 1 mol of gaseous species
Def of enthaply of atomisation (element)
Enthalpy change when 1 mol of gaseous atoms is formed from its element in its standard state
Def enthalpy of atomisation (compound)
Enthalpy change when 1 mol of a compound in gas state is converted into separate gaseous ions
Def bond dissociation enthalpy
Enthalpy change when 1 mol of given covalent bond, of a compound in the gas states is broken
Def of first electron affinity enthalpy
Enthalpy change when 1 mol of electrons is added to 1 mol of gaseous species
Def of lattice enthalpy (also called lattice formation)
Enthalpy change of formation of 1 mol of an ionic lattice from its gaseous ions
Def of enthalpy of hydration
Enthalpy change when one mole of gaseous ions are diluted to give no further temperature change and one mole of hydrated ions
Def of enthalpy of solution
Enthalpy change when 1 mole of solute is dissolved in sufficient solvent to give no interaction between dissolved species
Symbol and example equation for the first ionisation enthalpy
(Use sodium)
Δ1st i.e H⦵
E.g Na (g) —> Na+ (g) + e-
Symbol and example equation for enthalpy of atomisation of an element
(Use sodium and chlorine)
ΔatH⦵
E.g Na(s) —> Na (g)
1/2 Cl2 (g) —> Cl2 (g)
Symbol and example equation for the enthalpy of atomisation of a compound
(Use methane)
ΔatH⦵
E.g CH4 —> C(g) + 4H(g)
Symbol and example equation for bond dissocation enthalpy
(Use methane)
ΔdissH⦵
E.g CH4 (g) —> CH3 (g) + H (g)
Symbol and example equation for first electron affinity enthalpy
(Use sodium)
Δ1st eaH⦵
E.g Cl (g) + e- —> Cl- (g)
