enthalpy Flashcards
df 1st ionization en
en 2 remove 1 mol e- from 1 mol gaseous atoms
ionization trends
more en if go across oerodic table ie ->, less if go down eg F->Cl
df amount of heat absorbed or given out in rxn at const press
enthalpy change (delta H)
df standard enthalpy change (delta H superscript O
amount of heat ‘evolved or absorbed’ under stndard conditions (25OC, 1 bar press, solutions of conc 1mol/dm3
df standard state
state of ele in standard conditions ie 25OC. if allotropes, take most energetically stable eg grsphite instead of diamonds 4 carbon
df standard enthalpy change of formation
enthalpy change when one mole of compound is formed in standard conditions, and with everything in its standard state
equation for standard enthalpy change of formation of wr
h2+1/2 O2 -> h2o /\Ho= -286KJ/mol (must only be 1 mol of compound of interest
equation of Standard enthalpy change of combustion of H2
h2+1/2 O2-> H2O /\HO= -286 (must be 1 mol o ele combusted
DF Standard enthalpy change of combustion
enthalpy change of complretely burning 1 mole of the compound in oxygen under standard conditions, with everything in its standard state.
df empirical formula
formula showing the simplest ratio of elements in a compound eg hydrogen peroxide-> HO
cr relative x (eg formula) masses
mass of x in u (1/12 C-12 atom) x= ion for formula
df periodicity
trends in elements going down or across the periodic tsble
df electrophile/ nucleo
elect= reactant tt accepts pair e- 2 form covalent bond, nuc provides
df lattice enthalpy
str o forces bn ions in solid ionic cpd- either lattice formation or dissociaiton enth
df atomization enthalpy
enth change 2 form 1 mol of gaseous atoms from ele in its standard state (aa +ve value
