Enthalpy, entropy, free energy Flashcards
ΔLEH⦵
enthaply change when 1 mole of a solid ionic compound is formed from its gaseous ions
ΔfH⦵
enthalpy change when 1 mole of a compound is formed from its elements
ΔatH⦵ (element)
enthalpy change when 1 mole of gaseous atoms is formed from an element
ΔatH⦵ (compound)
enthalpy change when 1 mole of a compound is converted to gaseous atoms
ΔhydH⦵
enthalpy change when 1 moles of gaseous ions is dissolved in water
ΔsolH⦵
enthalpy change when 1 mole of solute is dissolved in a solvent, such as water
is ΔatH⦵ always endo or exothermic
endothermic, as bonds must be broken for it to happen
What are standard conditions
100kPa (1atm) 298K (25°C)
are first/second ionisation energies always endo or exothermic
endothermic, must overcome the attraction between electrons and nucleus
is first electron affinity endo or exothermic
exothermic
is second electron affinity endo or exothermic
endothermic
what are the 2 factors that affect lattice enthalpy
-ionic charge -ionic radius
how does ionic charge effect lattice enthalpy
higher charges on ions -> stronger electrostatic attraction between ion -> more energy released when lattice forms -> more negative enthalpies
how does ionic radius effect lattice enthalpy
smaller ionic radii of ions formed, higher the charge density of the ion. greater electrostatic attraction between ions, so lattice more exothermic.
how do you calculate ΔsolH⦵
-ΔLEH + ΣΔhydH