Osmosis Questions Flashcards
(14 cards)
What is osmosis?
The movement of water from a dilute solution to a concentrated solution through a partially permeable membrane.
What might you be asked to plan in this practical?
An investigation using plant tissue and different concentrations of salt/sugar solutions.
What is an example of a method for the osmosis practical?
Cut equal-sized pieces of plant tissue, weigh them, place them in different concentrations of solution, remove after set time, dry, and reweigh.
What is the independent variable in the osmosis practical?
The concentration of the salt or sugar solution.
What is the dependent variable in the osmosis practical?
The change in mass of the plant tissue.
What is an important control variable in this experiment?
Drying the cylinders before reweighing to avoid false mass readings.
Why is it important to dry the plant cylinders before reweighing?
To remove surface water that would make them appear heavier.
What is the formula for percentage change in mass?
(Change in mass ÷ starting mass) × 100.
Why is percentage change used instead of just final mass?
To allow fair comparison if starting masses were different.
What does no change in mass indicate in an osmosis experiment?
There was no net movement of water—internal and external concentrations are equal.
How can you estimate the concentration of the plant cytoplasm using a graph?
Find where the line crosses the x-axis—this is the concentration where there is no net change in mass.
What could you be asked to suggest based on a method?
Improvements to increase accuracy or reliability.
What might you be asked to calculate in this practical besides percentage change?
The rate of water uptake.
