2024-05-28T08:23:33+03:00[Europe/Moscow] en true <p>define Hess' Law</p>, <p>define standard enthalpy change of reaction</p>, <p>define standard enthalpy change of neutralisation</p>, <p>define standard enthalpy change of combustion</p>, <p>define standard enthalpy change of formation</p>, <p>define bond energy</p>, <p>define standard enthalpy change of atomisation</p>, <p>define ionisation energy(IE)</p>, <p>define electron affinity(EA)</p>, <p>define standard enthalpy change of hydration</p>, <p>define standard enthalpy change of solution</p>, <p>define lattice energy(LE)</p>, <p>define heat change, q</p>, <p>formula for standard enthalpy change of formation</p>, <p>formula for standard enthalpy change of combustion</p>, <p>formula for enthalpy change using bond energies</p>, <p>how to draw energy cycle</p>, <p>formula for enthalpy change of solution</p> flashcards
H2 Chemistry 4 - Energetics(i)

H2 Chemistry 4 - Energetics(i)

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  • define Hess' Law

    enthalpy change from chem rxn is the same regardless of route chem rxn occurs, provided initial, final states are the same

  • define standard enthalpy change of reaction

    heat change when molar quantities of rxts, as specified in chem eqn, react completely to form pdts USC of 298K, 1 bar.

    +/- (q / nLR) x coefficient of LR

  • define standard enthalpy change of neutralisation

    heat evolved when 1 mol H2O formed from rxn of acid & alkali USC of 298K, 1 bar

    - (q / nH2O)

  • define standard enthalpy change of combustion

    heat evolved when 1 mol substance completely burnt in excess O2 USC of 298K, 1 bar

    -(q / nsubs burnt)

  • define standard enthalpy change of formation

    heat change when 1 mol substance formed from constituent elements in their std states USC of 298K, 1 bar

  • define bond energy

    heat absorbed when 1 mol covalent bond b/w 2 atoms in gaseous state broken

  • define standard enthalpy change of atomisation

    heat absorbed when 1 mol gaseous atoms formed from constituent element in std state USC of 298K, 1 bar

  • define ionisation energy(IE)

    heat absorbed when 1 mol e- removed from 1 mol gaseous atom, forming 1 mol gaseous cation

  • define electron affinity(EA)

    1st EA

    heat evolved when 1 mol e- added to 1 mol gaseous atom, forming 1 mol gaseous anion

    succeeding EA

    heat absorbed when 1 mol e- added to 1 mol gaseous anion, forming 1 mol gaseous anion(-1)

  • define standard enthalpy change of hydration

    heat evolved when 1 mol gaseous ions hydrated USC of 298K, 1 bar

    proportional to charge density of ion

  • define standard enthalpy change of solution

    heat change when 1 mol substance completely dissolved in enough H2O USC of 298K, 1 bar such that no further heat change upon adding more H2O

  • define lattice energy(LE)

    heat evolved when 1 mol solid ionic compound formed from gaseous ions

  • define heat change, q

    q=msoln x csoln x change in temp

    efficiency%/100 x total heat change q

  • formula for standard enthalpy change of formation

    ΔH = ΣxΔHf (pdt) - ΣyΔHf (rxt),

    where x, y = stoichiometric coefficients

    FPMR

    Formation is Product Minus Reactant

  • formula for standard enthalpy change of combustion

    ΔH = ΣxΔHc (rxt) - ΣyΔHc (pdt),

    where x, y = stoichiometric coefficients

    CRMP

    Combustion is Reactant Minus Product

  • formula for enthalpy change using bond energies

    ΔH = +BE(bonds broken in rxt) - BE(bonds formed in pdt)

  • how to draw energy cycle

    FAIL

    Formation

    Atomisation

    Ionisation(IE & EA)

    Lattice Energy

  • formula for enthalpy change of solution

    ΔHsoln = -LE + ΣΔHhyd