Question

CRITICAL THINKING QUESTIONS 1. A pre-weighed dialysis bag which contained a solution of 10% glucose was placed in a beaker containing a solution of 20% glucose. After one hour, the bag was weighed again a. Calculate the % mass change of this dialysis bag from the following information: • Mass of bag before experiment: 15.39 • Mass of bag after experiment: 12.79 b. Determine the tonicity of the beaker when it is compared to the dialysis bag: 2. facell had 7% solute concentration and its environment had 15% solute concentration, what direction would water move? __Does this happen through diffusion or osmosis? What solution is the environment? 3. When people become seriously dehydrated and are rushed to the emergency room they are given an IV drip. The problem with people who are seriously dehydrated is that they do not have enough water to conduct necessary chemical reactions. They need water, but the IV isn't just water, it is full of ions (sodium, chloride, potassium, and calcium). If what the person is missing is water, why does the IV not contain only water? Explain your answer. 4. Before refrigeration it was a common practice to salt meat in order to prevent bacterial growth and decay of meat. Propose an explanation for how this process prevented bacterial growth 5. A bacterial cell is filled with proteins, nucleic acids, carbohydrates, sugars, amino acids. and many other molecules. As the cell moves about in a watery environment- a. What will happen to the cells when placed in distilled water? 108 Diffusion and Osmosis: Worksheet laboratory 6

Answer 1

1a. Mass of bag before experiment = 15.3 g
Mass of bag after experiment = 12.7 g
Percent change = [(15.3-12.7)/15.3] X 100
= 16.99%

1b. Bag = 10%
Beaker solution = 20%
i.e. the bag is hypotonic to the beaker solution resulting in the exosmosis of water into the beaker.
i.e. Water moves from high water potential to low water potential
Water moves from hypotonic solution to hypertonic solution

2. Cell = 7% solution
Environment = 15% solution
i.e. the cell is hypotonic to the environment resulting in the exosmosis (OSMOSIS) of water into the environment.
Cell = Hypotonic solution
Environment = Hypertonic solution