Solutions Part 2

what is a colligative property

when 4 physical properties are affected in the same way as solutes

what are the 4 main colligative properties

• vapour pressure lowering

• freezing point depression

• boiling point elevation

• osmotic pressure

why is osmotic pressure really important

as it contributes to the flow of nutrients through biological cell walls

what is the osmotic pressure

when a solution is seperated from its solvent by a membrane then the excess pressure which has to be applied to prevent the flow of solvent is known as

how do you calculate the osmotic pressure

USING THE VAN’T HOFF EQUATION

pi = RT x molarity

R = gas constant

T = temprature

what is the van’t hoff equation used for

to calculate osmotic pressure

what is hydrostatic pressure

pressure exerted by a column of aqueous solution or water

what is reverse osmosis

when a pressure (greater than osmotic pressure) forces the solvent through the membrane

what is dialysis

a seperation process based on equal rates of passage of solute and solvent through microporou membranes

what is an effect of osmosis

when a plant is dehydrated it will wilt

how can greater osmotic pressure affect red blood cells

water will pass out to reduce chemical potential across cell membrane ( cell shrinks)

how can lower osmotic pressure affect red blood cells

water will enter the cell ( cell swells) and eventually breakdown

what is an isotonic solution

when there is no net flow of solvent when the solutions are separated by a biological membrane

when the phase change is vapour to solid what is it called

deposition