thermodynamics Flashcards
standard enthalpy of formation
the enthalpy change when one mole of compound is formed from its elements, under standard conditions, all reactants and products in their standard states
first ionisation enthalpy
the standard enthalpy change when one mole of electrons is removed from one mole of gaseous atoms to give one mole of gaseous ions with a single positive charge
atomisation
enthalpy change when one mole of gaseous atoms are formed from an element in its standard state
mean bond enthalpy
-enthalpy change when one mole of gaseous molecules each break a covalent bond to form 2 free radicals
-over an average number of compounds
first electron affinity
standard enthalpy change when one mole of gaseous atoms is converted into one mole of gaseous ions each with a negative charge under standard conditions
lattice formation enthalpy
standard enthalpy change when one mole of solid ionic compound is formed from its gaseous ions
lattice dissociation enthalpy
standard enthalpy change when one mole of solid ionic compound dissociates into its gaseous ions
standard enthalpy of hydration
standard enthalpy change when one mole of gaseous ions is converted into one mole of aqueous ions
standard enthalpy of solution
standard enthalpy change when one mole of solute dissolves to form its aqueous ions
what 2 factors determine how exothermic a lattice enthalpy will be
-charge of ions
-size of ions
CRAM
-charge
-radius
-attraction
-more exothermic/endothermic
size of ions
smaller the ion, the greater the attraction to an oppositely charged ion
charge on ions
greater the charge, stronger the attraction to an oppositely charge ion
what is covalent character
ionic attraction between:
small positively charged ion
big negatively charged ion
theoretical model
PERFECT IONIC MODEL
- perfect spheres/point charges
-purely ionic bonding
