Enthaply and Entropy Flashcards
lattice enthalpy
∆H when one mole of a solid lattice is formed from its constituent gaseous ions under standard conditions
why can lattice enthalpy not be measured directly
because it impossible to form one mole of an ionic lattice from its gaseous ions
enthalpy change of formation
∆H when one mole of a compound is formed from it constituent elements in their natural state
enthalpy change of atomisation
∆H when one mole of gaseous ions is formed from its element in its standard state
enthalpy change of ionisation
∆H when one electron is removed from each atom in one mole of a gaseous atoms to form one mole of +1 ions
enthalpy change of solution
∆H one mole of a compound is dissolved in water under standard conditions
enthalpy change of hydration
one mole of aqueous ions are formed from their gaseous ions under standard conditions
enthalpy change of electron affinity
when each atom in 1 mole of gaseous atoms accepts an electron to form one mole of -1 ions
what affects lattice enthalpy and how
ionic radius - if it increase the attractions between ions decreases meaning the lattice enthalpy is less exothermic
ionic charge- if it increases so does the attraction making the lattice enthalpy more exothermic
what affects ∆H of hydration
∆H of hydration is dependent on the ability for the ions to attract water molecules
if ionic radius increases the ∆H becomes more positive
if ionic charge increases ∆H of hydration becomes more negative
how does amount of disorder relate to entropy
More disorder means positive entropy value less disorder (more ordered) means negative entropy value
how to work out entropy change
products - reactants
what is free energy change
balance between enthalpy and entropy to determine the feasibility of reactions
