enthalpy changes Flashcards
enthaply change of formation
enthalpy change when 1 mol of a compound if formed from its elements
Enthalpy change of atomisation of element
1 mol of gaseous atoms formed from its elements
enthalpy change of atomisation of compund
1 mol of compound converted into gasoues atoms
first ionisation energy
Energy needed to chage 1 mol of gasous atoms into 1 mol of gaseous 1+ atoms
second ionisation energy
change 1 mol of gaseous 1+ atoms into +2 atoms
first electrn affinity
energy needed to change one mol of gaseous atoms into 1 mol of gaseous 1- atoms
second electron affinity
one mol of gaseous 1- atoms into one mol of 2- gaseous atoms
Lattice enthaply
1 mol of a solid ionic compound formed from its gaseous ions
Enthalpy change of hydration
1 mol of gasous ions dissolved in wotar
enthaply change of solution
1 mol of solute dissolved in a solvent eg water
Write an equation for the process that has an enthalpy change equal to the electron affinity of chlorine.
Cl(g) + e- → Cl-(g)
In terms of electrostatic forces, suggest why the electron affinity of fluorine has a
negative value.
There is an attraction between the nucleus/protons and (the added) electron(s)
Energy is released (when the electron is gained)
Explain why there is a difference between the hydration enthalpies of the magnesium and sodium ions.
magnesium (ion) has a higher charge
Explain why the theoretical enthalpy of lattice dissociation for silver fluoride is different from the experimental value that can be calculated using a Born–Haber
cycle.
Experimental lattice enthalpy value allows for / includes covalent interaction / non–spherical ions / distorted ions / polarisation
What does a larger exothermic value tell you about lattice enthalpy
- a stronger ionic bond
