Osmosis P1 Flashcards
What are you investigating during Osmosis?
Investigate the effect of a range of concentrations of salt or sugar solutions on
the mass of plant tissue.
What materials should you use to investigate Osmosis?
Materials For the basic method In addition to standard laboratory equipment: • a potato • a cork borer • a ruler with mm scale • labels or a permanent marker • paper towels • a sharp knife or scalpel • a top-pan balance accurate to at least 0.01 g • a range of sugar or sodium chloride solutions (0.25−1.0 mol/dm3) • distilled water.
Define osmosis
A process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.
How can you investigate the effect of sugar solution of plant tissue?
Test of Osmosis
- Cut potato into identical cylinders and get beakers of different sugar solutions. One with pure water.
- Measure and record the mass of each cylinder and leave for 24 hours
- Dry with a paper towel and measure mass again
- Take away the initial mass from final to get the change in mass.
- Repeat with same concentrations to find a more reliable mean.
- You can plot and when crosses line this is same concentration in potato as in solution.
What conclusions can be drawn from a test of sugar solution?
- if draw in water they will increase in mass and concentration of sugar in solution is lower than in potato. Hypotonic solution
- If lose mass then concentration of sugar is greater in solution. Hypertonic solution
What variables are considered during the osmosis practical?
Dependent - chip mass
Independent - concentration of solution
Control variables - volume of solution, temperature, time, type of sugar used
What errors may there be during the osmosis practical?
- if not fully dried they may have a higher mass
- if water evaporates from the beakers the concentrations of sugar will change
Reduce by repeating and finding a mean.
