Energetics Flashcards
Define the standard enthalpy change of combustion.
The energy evolved (-) when ONE mole of the substance is COMPLETELY burnt in oxygen under standard conditions.
Define the standard enthalpy change of neutralisation.
The energy evolved (-) when ONE mole of WATER is formed from the neutralisation between acid and base under standard conditions.
Define the standard enthalpy change of formation.
The energy change (+/-) when ONE mole of substance is formed from its constituent ELEMENTS under standard conditions.
Define bond energy.
It is the average energy absorbed (+) to break ONE mole of X-Y covalent bonds (state explicitly in context of qn) in the GASEOUS STATE to form GASEOUS atoms under standard conditions.
Define Lattice energy.
The energy evolved (-) when ONE mole of the solid ionic compound is formed from its constituent GASEOUS IONS under standard conditions.
Define the standard enthalpy change of atomisation.
The energy absorbed (+) when ONE mole of GASEOUS ATOMS is formed from the element under standard conditions.
Define 1st I.E.
The energy absorbed (+) to remove ONE mole of electrons from ONE mole of gaseous atoms to form ONE mole of singly positively charged gaseous ions.
[note: even for non-metals]
Define 2nd I.E.
The energy absorbed (+) to remove ONE mole of electrons from ONE mole of singly positively charged ions to form ONE mole of doubly positively charged gaseous ions.
[note: even for non-metals]
Define first electron affinity.
The energy evolved (-) when ONE mole gaseous atoms acquires ONE mole of electrons to give ONE mole of singly negatively charged gaseous ions.
Define the standard enthalpy change of hydration.
The energy evolved (-) when one mole of GASEOUS IONS is hydrated under standard conditions.
Define standard enthalpy change of solution.
The energy change (+/-) when one mole of the substance is completely dissolved in a solvent to form an infinitely dilute solution under standard conditions.
Define entropy (S) and state its units.
Entropy measures the degree of disorder in a system.
Units: J K-1 mol-1
What are the “standard conditions”?
298K and 1 bar.
What are the units for Gibbs free energy?
J mol-1
(or kJ mol-1)
