Question: Is A Plastic Bag A Semipermeable Membrane?

What will happen to the color of the water and iodine solution Why?

Color change is often used as an indicator of a chemical change or reaction.

In the first experiment, the iodine and water solution are a dark brown color until the starch is added.

Then the solution changes to a dark bluish-black color.

This happens because the iodine bonds with the starch to create a new compound..

Can iodine pass through Visking tubing?

The iodine solution stayed the same brown colour. This is because the visking tubing is only semi-permeable and only allows particle smaller than the pores of the tubing. … The iodine solution molecules were small enough to pass through the pores of the tubing and reacted with the starch molecules inside of the tubing.

Why was iodine able to diffuse across the membrane while starch was not?

Answer and Explanation: Iodine was able to diffuse across the membrane because it is small and hydrophobic and starch was not because it is too large.

What is an example of a semipermeable membrane?

An example of a semipermeable membrane is a cell membrane. By keeping the inside of a cell at low concentration, it can keep absorbing the molecules it needs. This is used by most cells, including the roots of plants, which use osmosis to absorb the water and nutrients they need.

What would happen if you put iodine in a plastic bag?

The conclusion to this test is that the plastic bag is permeable to iodine. … M.y hypothesis was that the iodine will get into the bag of starch because the baggie is permeable to iodine. If the iodine solution penetrates the bag, it will turn the starch solution inside the baggie, purple.

Does iodine react with plastic?

Iodine can leave the plastic and react with something you put inside the tube. Hence, the best idea is to dispose the tube after taking a picture as a memento of your experiment!

What does a semipermeable membrane allow?

Semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain molecules or ions to pass through it by diffusion—or occasionally by more specialized processes of facilitated diffusion, passive transport or active transport.

Can salt pass through a semipermeable membrane?

The dialysis tubing is a semipermeable membrane. Water molecules can pass through the membrane. The salt ions can not pass through the membrane. The net flow of solvent molecules through a semipermeable membrane from a pure solvent (in this cause deionized water) to a more concentrated solution is called osmosis.

Are Ziploc bags permeable?

The permeability of the bag is improved(reduced) by the metallization; it’s much harder to diffuse water through a metal film than through a plastic one. … A Ziploc-type bag has an extremely poor seal, as well as high permeability.

Are plastic bags airtight?

A ziploc bag is airtight, yet scents from inside the bag will still permeate the plastic over time. … Scent molecules are certainly larger than water molecules, so there must be some other phenomenon, like what Staus says above regarding nonpolar molecules diffusing through plastic.

What is the difference between osmosis and diffusion?

Osmosis: Osmosis is the movement of solvent particles across a semipermeable membrane from a dilute solution into a concentrated solution. … Diffusion: Diffusion is the movement of particles from an area of higher concentration to lower concentration.

How is the plastic bag like a cell membrane?

A plastic sandwich bag is a good model of a cell membrane. Like a cell membrane, it has millions of invisible tiny holes that allow small molecules to pass through. … The sandwich bag and the cell membrane are selectively permeable. This can be demonstrated using iodine and starch.

Why didn’t the starch enter the beaker?

Because starch had larger molecular size, the dialysis tubing was not permeable to it (it didn’t allow it to readily pass through the pores of its membrane).

What can pass through the semipermeable membrane?

A semipermeable membrane is a layer that only certain molecules can pass through. While water and other small molecules can slip through the gaps between the phospholipid molecules, other molecules like ions and large nutrients cannot force their way into or out of the cell. …

Why does vitamin C turn iodine clear?

Iodine also binds to ascorbic acid. When it binds to vitamin C, it is colorless. Iodine binds more strongly to ascorbic acid than it binds to starch. The iodine, therefore, leaves the starch and binds to ascorbic acid, which would make the blue solution become clear.”

Why does iodine change the color of starch?

Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The iodine molecule slips inside of the amylose coil. … This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black color.

Why is it not good idea to store iodine in a plastic bag?

The Baggie isn’t permeable to starch because it didn’t move because it is too big of a molecule. Since the Baggie allowed the iodine to go through it is selectively permeable. … I learned that it is not a good idea to store iodine in a plastic bag because it would leak out and stain everything.

Is a plastic bag selectively permeable?

4. Is the plastic baggie selectively permeable? Yes it is a selective permeable membrane, because it only allowed certain substance to pass through. In this case it stopped the water molecules in the iodine substance and allowed on the iodine itself to go through it.

How is the cell membrane similar to a plastic bag with tiny holes?

Cell Membranes All cells are contained by a cell membrane that keeps the pieces inside. When you think about a membrane, imagine it is like a big plastic bag with some tiny holes. That bag holds all of the cell pieces and fluids inside the cell and keeps any nasty things outside the cell.

Why can iodine pass through a membrane?

The Dialysis tubing provides a semi-permeable membrane. Only allowing smaller molecules to pass through it. Iodine molecules are small enough to pass freely through the membrane, however starch molecules are complex and too large to pass through the membrane. … Thus iodine diffused into the tube with the starch.

What does iodine do to potato cells?

The iodine is having a chemical reaction with the starch in the potato. When the iodine finds the long, straight chains of sugars in the starch, they attach to each other and get twisted. The result looks more like a spiral than a straight chain, and it results in the purple or blue color you’re seeing.