lecture 1 fr Flashcards
ideal chemical potential
uB = uB• + RT ln (xB)
chemical potential = chemical potential at standard state + RT ln(mole fraction)
real chemical potential
it’s affected by ion activity!
uB = uB• + RT ln(ab)
chemical potential = chemical potential at standard state + RT ln (activity coefficient x mole fraction)
what is aB
aB = mole fraction x activity coefficient
accounts for the deviation from ideal behaviour
what is henry’s law
links vapour pressure + chemical potential
uB = uB* + RT ln(pB/pB*)
chem pot = pure chem pot + RT x ln (pressure / pure pressure)
how do we find pB (pressure of B)
mole fraction x coefficient
XA x KB
when is the solution ideal
when the KB constant is equal to the pressure of pure solute pB*
what do we replace mole fraction with for simplicity
we replace it with molality
number of moles // amount of solvent (kg)
with is mB or bB
molality
what is b•
molality at standard states
chemical potential equation using molality
uB = uB• + RT ln( bB or mB) // b•
if b• is equal to bB or mB what happens
uB is equal to uB•
there is no deviation
how do we find aB for uB= uB• + RT ln (aB)
aB = yB (bB or mB)// b•
what does activity coefficient do
captures deviations from ideal behaviour
deviations from ideality can occur due to what
strong inter ionic forces due to electrostatic forces of attraction
in very dilute solutions what can happen
activity can we replaces with molality ( mB or bB)
