2/26 osmotic pressure Flashcards
what is osmosis
the flow of solvent across a semi permeable membrane
what is osmotic pressure
it is the pressure that exists inside the cell when solvent flows through the membrane
what is a binary solution
it is a mixture of two volatile liquids where both liquids can enter the gas phase
what does it mean when the composition of A in the vapor phase is greater than its composition in the liquid phase? (YA>XA)
it means the solution is highly volatile and enriches the gas phase
when a compound is more volatile, what is always true
its YA> XA and it enriches the vapor phase
if a compound has a larger vapor pressure what does that mean about its likelihood to go into the gas phase
it is more volatile and will likely be in the gas phase
if a compound has a smaller vapor pressure, what does that mean about its likelihood to go into the vapor phase
it is less volatile and less likely to be in the gas phase
Raoult’s law and isothermal distillation only work with
ideal solutions
what is an ideal solution
it is a solution where the interactions between all pairs of molecules are equivalent/ equal in strength
A-A, B-B, A-B have the same strength
a mixture between benzene and toluene is what type of solution
it is an ideal solution
a mixture between ethyl bromide and ethyl chloride is what type of solution
it is an ideal solution
a mixture between pentane and hexane is what type of solution
it is an ideal solution
what is the general condition for an ideal solution
it is when A + B have a similar size and structure, they will have the same strength of intermolecular forces throughout
what is a non ideal solution
it is a solution where the interactions between the components are not the same
what are the two types of non ideal solutions
1) when A-A/ B-B interactions are stronger than A-B interactions
ex) oil-oil/ water-water
2)
when mixing oil and water, what type of non ideal solution is it
it is when the A-A interactions are stronger than the mixed interactions.
ex) oil and water do not want to interact with eachother
for solutions where the interactions between A-A and B-B are stronger than A-B, what type of deviation to Raoult’s law do they have
they have a positive deviation since the actual pressure is larger
for solutions where the interactions between A-A and B-B are stronger than A-B, what type of phase does the solution favor?
it has a higher tendency to be in the gas phase since the molecules do not want to be near eachother, this results in a higher pressure
for solutions where the interactions between A-B are stronger than A-A and B-B, what type of deviation from Raoult’s do they have?
negative deviation, the actual pressure is smaller
for solutions where interactions between A-B are stronger, what phase do they have a tendency for? what does this do to the pressure
they want to stay in solution so the vapor pressure will be lower
in terms of distillations, how do nonideal and ideal solutions differ?
in ideal solutions, you can separate the two components
for non-deal solutions, you cannot separate the two components due to the presence of an azeotrope
why can non-ideal solutions not be separated by distillations
non-ideal solutions form an azeotrope where the liquid and vapor compositions are equal and the vapor phase cannot be more enriched in the volatile component past the intersection point
what does the kinetic energy of a gas molecule depend on
it depends only on the temperature, two gas molecules could have the same KE even if they are a different species
