Question

Osmosis occurs when there is a different concentration of solute molecules on each side of the membrane. The drawing below shows a beaker containing a 30% salt solution. A plastic bag containing a 10% salt solution is hanging down into the solution in the beaker. What will happen to the bag after about 20 minutes?

Answer 1

The membrane is not permeable to salt molecules, so all the salt molecules in the bag with salt solution will stay in the bag. And all the salt molecules in the rest of the beaker will stay there too. The key is that the only molecules that can move across the membrane are water molecules.

Molecules flow from an area where they are highly concentrated (i.e., there are many of them) to an area of low concentration. Always. So what you should do is identify whether there is a higher concentration of water molecules in the solution in the beaker, or the solution in the baggie in the middle. If there is a higher concentration of water molecules inside the baggie, water molecules will diffuse down their concentration gradient into the solution. If there is a higher concentration of water molecules in the beaker, they will diffuse down their concentration gradient into the baggie.

And if there is the same concentration of water molecules in the baggie and in the beaker, an equal number of water molecules will diffuse in and out of the bag. So there will be no net change in the total number of water molecules in each compartment.

Hope that's helpful. :)

Answer 2

ok so based on my knowledge and that i have taken bio before, i conclude that after about 20 minutes, the water will move from the bag into the 30% salt solution.
hope this helps :)