Enthalpy, Entropy And Free Energy Flashcards
What is the mean bond enthalpy
Average enthalpy change when one mole of a given bond is broken in a range of molecules
What is the standard enthalpy of formation
Enthalpy change when one mole of a substance is formed from its elements (in their standard states) under standard conditions
What is the standard enthalpy change of combustion
Enthalpy change when one mole of a substance is completely burnt in oxygen
What is the standard enthalpy of atomization
Enthalpy change when one mole of a gaseous atoms form from the elements in standard state
What is first ionization energy
Enthalpy change when one mole of atoms in gaseous state is converted to one mole of gaseous ions with a positive charge
What is second ionization energy
Enthalpy change when one mole of atoms in gaseous 1+ state is converted to one mole of gaseous 2+
What is the first electron affinity
Enthalpy change when one mole of gaseous atoms forms one mole of gaseous ions with a negative charge
What is second electron affinity
Enthalpy change when one mole of gaseous 1- atoms forms one mole of gaseous ions with a -2 negative charge
What is lattice enthalpy of formation
Enthalpy change when one mole of a solid ionic compound is formed from gaseous ions
What is the lattice enthalpy dissociation
Enthalpy change when 1 mole of a solid ionic compound is dissociated into gaseous ions
What is the standard enthalpy of hydration
Enthalpy change when one mole of gaseous ions from aqueous ions
What is the standard enthalpy of solution
Enthalpy change when 1 mole of solute forms a solution
Describe the enthalpy changes and diagram for born harbor cycle
Reactants in standard states-
Atomization
reactants (metals) in gaseous state
First ionization energy
Metal in + state
Atomization
Non metal in single form (X2->X)
Electron affinity
Non metal in - state
Lattice enthalpy of formation
Solid compound
For a reaction to be feasible what value does delta G have to have
Negative
What state has the highest entropy value
Gas, liquid, solid
What is the equation for delta G
Delta G= delta H -T delta S
how to calculate delta S (entropy)
Products - reactants
(sums of entropy)
how to calculate delta H (formation)
what causes a higher lattice enthalpy
increasing charge
smaller the ion size
large exothermic values of lattice enthalpy= large electrostatic force of attraction
why do smaller ions have larger lattice enthalpies
greater attraction due to higher charge density, larger lattice enthalpies and melting points due to extra energy needed to separate the ions
what increases the enthalpy of hydration
smaller ions
larger the charge of the ion
for diagram with enthalpy of solution and hydration at what levels do atoms go on
solid compound –> (enthalpy of solution)
(Aq) ions <– (hydration)
one (aq) ion and one in standard state <–(hydration)
gaseous ions–> (lattice enthalpy) to solid
what value of delta solH means its more likely to dissolve
the more negative
will a substance dissolve if delta solH is positive and very large
no
if delta solH is small and positive will it dissolve
may dissolve if there is sufficient energy
How does the Y=MC + C equation link to delta G equation
Y=MX+C
Delta G= -delta S T + delta H
How to calculate Q=MCdelta T equation with delta H, calculate delta T
Work out moles and X by delta H to get energy (J)
T= J/MC
