Osmosis Flashcards
What is osmosis?
Osmosis is the movement of water molecules across a partially permeable membrane from an area of higher concentration to an area of lower water concentration.
What is a partially permeable membrane?
A membrane with very small holes in it to allow small molecules through.
Which way do water molecules pass through the membrane?
Both ways, this is because water molecules move about randomly
What are the steps of the potato cylinder experiment?
First, you cut a potato into identical cylinders, and get some beaters with different sugar solutions. One should be pure waterand another should be a very concentrated sugar solution(e.g. 1mol/dm3). Then you can have a few others with concentrations in between ( e.g. 0.2 mol/dm3, 0.4 mol/dm3, etc)
Then you measure the mass of the cylinders, and leave one cylinder in each beaker for 24 hours or so.
Then you take them out dry them with a paper towel and measure their masses again.
If the cylinders have drawn in water by osmosis, they will have increased in mass. If water has been drawn out, they will have decreased in mass.
What is the dependent variable in the experiment?
The chip mass
What is the independent variable in the experiment?
The concentration of sugar solution.
What are the control variables in the experiment?
Volume of solution, temperature, time,type of sugar used, etc.
What are some errors that could occur in the experiment?
Potato cylinders not fully dried (excess water would give a higher mass) or if water evaporated from the beakers (the sugar concentrations would change)
