Consider an experiment in which starch is dissolved in a liter of water. Some of the solution is placed into a securely tied dia
lysis bag. The dialysis bag is placed into a beaker containing distilled water and iodine for 30 minutes. What are the correct answers for the questions below? (Note: Iodine reacts with starch to create a black/purple color.) What would happen to the color of the solution in the bag?
a. The solution in the bag would turn purple as the iodine reacts with the starch.
b. The solution in the bag would grow lighter as the starch leaves the bag and enters distilled water and iodine.
Would there be a color change in the water-iodine solution?
a. The water iodine solution has no color change.
b. The water iodine solution turns purple.
How do substances enter or leave the dialysis bag?
a. The dialysis bag is permeable to iodine so it can move into the bag but is not permeable to starch.
b. There is a leak in the bag allowing starch to flow out.
How would the mass of the bag change after a few hours?
a. The mass of the bag would be lighter as starch leaks out.
b. After several hours, the mass of the bag should increase as water moves by osmosis from the lower concentration outside the bag to the higher concentration (hypertonic solution).
Nitrogen group element, any of the chemical elements that constitute Group 15 (Va) of the periodic table. The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi), and moscovium (Mc).
