lab 3 Flashcards
define diffusion
movement of a substance from an area of higher concentration to one of lower concentration due to kinetic energy ( down CG)
define osmosis
movement of water molecules across a selectively permeable membrane until equilibrium
how does cold temp affect diffusion? (crystal lab)
in the ice bath, molecules have less energy to diffuse so diffusion rate is slower (hardly purple)
how does diffusion work at room temp? (crystal lab)
diffusion is slower and takes longer (light purple)
how does hot temps affect diffusion? (crystal lab)
particles have more energy therefor they diffuse faster. high CG to low CG until equilibrium (purple colour)
explain what happened when IODINE was in the bag and STARCH was outside of the bag.
-the bag crenates
-higher solute. concentration outside of bag caused net movement of water out of the bag. (water & iodine leave bag)
-iodine leaves by diffusion, water leaves by osmosis
-hypertonic
-iodine leaving bag caused starch solution to turn blue/black
-moves down CG
-volume of bag decreases and vol in beaker increases
explain what happened when STARCH was inside the bag and IODINE was outside of the bag
-bag swells and volume increases
-water and iodine move into bag through osmosis and diffusion
-bag is hypotonic because water and iodine move into it
-volume in beaker decreases and vol in bag increases
-net movement of water into bag
-iodine binds w starch for colour in bag
what is a dilute solution?
small amount of solute in solution, low concentration
what is a concentrated solution?
a solution that contains a large amount of solute, high concentration
what is a solutions tonicity?
tonicity refers to the ability of a solution to change shape or tone by changing the volume of water they contain
what is hypertonic?
external solution that has a high solute concentration, this causes net movement of water out of cell, where the cell will crenate
what is hypotonic?
external solution has a lower solute concentration, causes net movement of water into the cell, the cell will swell and hemolyze (burst)
what is isotonic?
external solution has the same solute concentration as inside the cell, causing no net movement of water and the cell will stay the same normal shape
what is the shape of red blood cells
RBC are smooth and round with concave center
why did the weight of the egg decrease in 42% sucrose?
the egg got lighter because the sucrose solution is hypertonic to the egg, meaning it has more dissolved particles and less water. the higher concentration of water in the cell and lower concentration of water outside of the cell made water move by osmosis out of the egg. water moved down concentration gradient from egg-solution. this makes egg weigh less.
