UNIT 1 Section 7 - Thermodynamics Flashcards
What is Lattice enthalpy of formation
The enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions
What is Lattice dissociation enthalpy
The enthalpy change when 1 mole of a solid ionic compound is completely dissociated into its gaseous ions
What is Enthalpy change of solution
When one mole of a solid ionic substance dissolves in water to produce aqueous ions in an infinitely dilute solution
What is Enthalpy of formation
when elements in their standard states form 1 mole of a compound in standard states under standard conditions
what factors affect enthalpy of hydration
the partial charges of water that are attracted to the ions
the partial charges of water are more strongly attracted to smaller ions
what is the definition of the enthalpy of atomisation
when the elements in their standard states form one mole of gaseous ions
what is the enthalpy of hydration
when 1 mole of aqueous ions is formed from gaseous ions
what factors can produce covalent character
small highly charged positive ions in the lattice
large highly charged negative ions
what properties does covalent character affect
the solubility (less) and the conductive ability (less)
what is entropy
the measure of disorder or randomness in a system
factors that affect entropy
- state matter
- energy of the particles
- dissolving the substance
- number of particals
when is a reaction feasible
when the delta G=0
what is ionisation energy
the amount of energy required to remove one mole of electrons from one mole of gaseous ions
what is enthalpy of atomisation
enthalpy change when 1 mole of gaseous atoms is formed from its element under standard conditions
what is Kp
the ratio of products and reactant concentration in terms of their paritial pressuresi
what is the equation for Kp
Kp= (ppc)y x (ppd)z
———————–
(ppa)w x (ppb) x
what is the equation for partial pressures
pp = mole fraction x total pressure
what is the mole fraction
no. moles of species / total number of moles of all species
what are the factors that effect lattice enthalpy
radius- the smaller the ion the stronger the bonds
charge- the higher the charge the stronger the bonds
what does a reaction being feasible mean
that once the reaction has started it will carry onto completion without energy being supplied to it
what is the equation for entropy change
enthalpy change= S products- S reactants
what is the free energy change equation
delta G = delta H - TdeltaS
what are the units for the free energy change equation
temperature = kelvin
delta G = j/mol
delta S = J/K/mol
if delta H and delta S are both positive what is the feasibility like
low temps not feasible
high temps are feasible
if delta H is negative and delta S is negative what is the feasibility like
Low temps feasible
High temp not feasible
if delta H is positive and delta S is positive what is the feasibility like
Low temps not feasible
High temp feasible
if delta H is positive and delta S is negative what is the feasibility like
never feasible
