practical: osmosis Flashcards
what piece of apparatus is used to measure mass
balance
what piece of equipment is used to measure time
stopwatch
what is osmosis
the movement of water through a selectively permeable membrane from an area of high water concentration to a lower concentration of water
why would you dry the potato before weight it again
so that excess water does not contribute to the mass
why do you calculate the percentage change in mass
the samples would have been different masses
what are some of the potential sources of error when investigating osmosis
concentration of solutions, drying off pieces before weighing, accuracy of balance, evaporation from tubes
when would a potato left in solution increase in mass
the solution would be more dilute than the potato piece and so water has entered the potato by osmosis
when would a potato piece left in solution decrease in mass
the solution would be more concentrated than the potato piece and so water has left the potato by osmosis
when would a potato piece left in solution not have a change in mass
when the concentration of the solution is the same as the concentration of the potato
what are the control variables when determining the concentration of the potato piece
time in solution, surface are of potato piece, volume of solution, amount of blotting dry
how could you increase the reliability of investigative data
do repeats
how do you calculate the percentage change in mass
divide the change in mass by the start mass and x100
what does it mean if you get a negative percentage change in mass
there has been a loss in mass
what does it mean if you get a positive percentage change in mass
there has been a gain in mass
