Question

Some students investigated osmosis in raw potato sticks. The students measured the mass of three potato sticks using an electronic balance. The students left each potato stick in one of the three different liquids for 5 hours:i. distilled water. ii. dilute sodium chloride solution. iii. concentrated sodium chloride solution. After 5 hours they measured the mass again and calculated the change in mass. 1. Predict which of the liquids would cause the largest decrease in mass of a potato stick. 2. After the experiment, the students noticed that the potato stick with the lowest mass was soft and floppy. Explain why the potato stick had become soft and floppy. 3. The students followed the same experimental procedure with boiled potato sticks and found no overall change in mass in any of the solutions. Suggest why the mass of the boiled potato sticks remained the same.

Answer 1

Answer:

1. The liquids that will cause the largest decrease in mass is the concentrated sodium chloride solution

2. The reason why the potato stick with the lowest mass was flaccid or soft and floppy because the cytoplasm of the cells has lost considerable amount of water to the concentrated solution of sodium chloride such that the once filled cell are now partially evacuated and having less turgor pressure

3. With the boiled potato sticks, the cells are dead and the (semi-permeable) membranes selectivity is no longer active, as such there is no preferential movement of water molecules between the salt solution and the boiled potatoes and no overall change is mass as the potatoes have become less responsive to changes in the surrounding solution.

Explanation: