Name: ____________________________________ Per. _____ Date: _____________________
Lab Partners: _______________________________ & ________________________________
Hocus Pocus Egg Osmosis Post Lab Analysis
How Solute Concentration Affects Osmosis
Work with your lab partners to analyze your data and draw conclusions
about the tonicity of the solutions the decalcified eggs were immersed in.
Additionally, use the knowledge gained from this lab to transfer this understanding to how the
cell membrane regulates what goes in and out of the cell.
Analyze:
1. Describe what happened to the egg that was immersed in the distilled water and use your data
to support your conclusion. .
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2. Describe what happened to the egg that was immersed in the 50% syrup and use your data to
support your conclusion.
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3. Describe what happened to the egg that was immersed in the 100% syrup and use your data
to support your conclusion.
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4. What would eventually happen to each of the eggs if they were left immersed in their
respective solutions? Explain your reasoning for each outcome.
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5. How would you classify each solution for tonicity?
a. Distilled water __________________________________
b. 50% Syrup __________________________________
c. 100% Syrup __________________________________
6. What similarities and differences did you see among and between the 50% syrup and the
100% syrup solutions in regards to their effect on osmosis with the eggs?
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7. Was the rate of percent change in mass constant for each solution or did it vary? Did it start
out slow and then increase? Dis it start rapidly then decrease in rate? Was it steady?
a. Describe each solution’s effect on the rate of percent change in mass of the egg
immersed and hypothesis why the rate of change exhibited the pattern/trend that it
did.
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Apply:
8. Human erythrocytes (red blood cells) are necessary for survival since they transport the
oxygen and carbon dioxide throughout our body to and from cells. Our blood consists of
anywhere from 35 to 50% erythrocytes and is the contributing factor to our blood being red
in color. Besides a small percentage of the blood being leukocytes (white blood cells) and
thrombocytes (platelets) the rest of the blood consists of liquid called plasma that is mostly
water with dissolved gases, organic and inorganic materials. The cell membrane of the
erythrocyte is permeable to water just as the egg membrane was and osmosis occurs. When
someone gets an I.V. in the emergency room, the Dr. orders “Normal Saline” which has a
NaCl concentration of 0.9%. This acts as an isotonic solution around the erythrocytes in the
blood.
a. What is the concentration of water and of NaCl in erythrocytes?
Water - _________________
NaCl - ______________________
b. What would happen to the erythrocytes if a solution containing a NaCl concentration
greater than 0.9% was used?
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c. What would happen to the erythrocytes if distilled water was used in the I.V.?
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