lecture 2 fr Flashcards
what interactions are very strong
coulomb (ion ion) interactions are very strong and get stronger as distance decreases
opposite charges
attract
what is a non uniform shell structure
ion charges alternate
+-+-+-
what is an ionic cloud
spherical haze of charge around an ion
what happens with ions of opposite charge
they form shells as they get closer to eachother
+ surrounded by - shell
- surrounded by + shell
they also overlap
what decreases overall energy
relaxation due to the clouds
difference between Gm and Gm ideal
+ RT ln(y+ y-)
what does shell size depend on
the concentration of ions
shell length
debye length
what does the debye limiting law do
helps us find Y+-
mean activity coefficient
what is y+-
mean activity coefficient
used for dilute solutions
what does the mean activity coefficient depend on
- ion charge (Z)
- ionic strength (I)
the closer the mean activity coefficient gets to 0,, what happens
the further away it gets from ideality
higher conc and higher ion charge = less ideality
equation to find mean activity coefficient y+-
y+- = - A | Z- Z+ | I^1/2
what is Z+ and Z-
the charge number!!
for each ion
u multiply them together
how do u find I,, ionic strength
I = 1/2 x { Z^2 x bB / b•
for some reason u kinda ignore b• tho lol,, u square the charge number
when is the extended debye huckel equation used
when ionic strength is higher than the expected ranges of linearity
what is plotted on the graph
mean activity coefficient ‘y’
against molality.
steeper negative line = due to higher conc or higher charge = loses ideality at a faster rate
