Question

4. The diagram below represents a laboratory setup used by a student during an investigation of diffusion.Distilled water is 100% water.Tube AGlass tubeTube BTubing10 mL ofdistilled water10 mL of watercontaining 5% starchDialysis membraneWhich statement best explains why the liquid in tube A will rise over a period of time?(1) The starch concentrations are equal on both sides of the membrane.(2) The water will pass from a region of lower starch concentration to one of higher starchconcentration.(3) Water and starch volumes are the same in both tubes A and B.(4) The fluids in both tubes A and B will change from a higher temperature to a lower temperature.In the diagram in #4, the starch will not move. Write a complete sentence explaining why.

Answer 1

A permeable membrane like the one used in the experiment allows only some types of molecules to pass through, the starch does not pass through the selectively permeable membrane bacause its molecules are to large and the form of the complex compound is too large to go through the pores. Complex molecules as carbohydrates can not pass a selectively membrane without using energy or/and other molecules carriers, the membrane in the experiment is for a dialysis process that only permit the osmmosis of ions and molecules with low mass as the water in the tube A and B.