A Grade 11 Biology student has prepared an experiment to demonstrate the effect of different factors on osmosis to the class. A potato cube is placed in a beaker filled with hot salt water and another potato cube is placed in a beaker filled with cold salt water.
a) What observations would his classmates record about the differences in size between the two potato cubes?
a) What observations would his classmates record about the differences in size between the two potato cubes?
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This is a trick question. You would expect that there would be a difference in the size of the potatoes but not so. First of all there is basically no change in the solubility of sodium chloride from 0 degrees Celsius to 100 degrees Celsius (temperature of the water that the salt is dissolved in). The solubility of sodium chloride is about 38g/ml regardless of the temperature of the water. Both cubes would shrink some what because of osmosis. Water will diffuse from where t here is more "pure" water (the cells of the potato) to where there is less "pure" water (the salt water surrounding salt water). This absolutely true. Look up the solubility of NaCl (sodium chloride) in water from 0 degrees to 100 degrees Celsius. It's almost a flatline.