Activity 3 Transport Processes Postlab

Activity 3: Transport Processes Postlab Discussion

DIFFUSION AND MOLECULAR WEIGHT: Part 1 What are formed upon the reaction of HCl and NH4OH? HCl + NH4OH

NH4Cl + H2O

DIFFUSION AND MOLECULAR WEIGHT: Part 2 1.

Which solution has diffused the farthest, congo red, KMnO4, or methylene blue?

MW: Congo red KMnO4 Methylene blue

= 697 = 158 = 319

DIFFUSION AND MOLECULAR WEIGHT: Part 2 1.

How does molecular weight affect the rate of diffusion?

Rate of diffusion is inversely proportional to molecular weight.

DIFFUSION AND TEMPERATURE Why is KMnO4 used in this experiment? IONS: Potassium = K+ Permanganate = MnO4 Because it is a salt that easily dissolves in water.  It dissolves in water to give deep purple solutions 1.

DIFFUSION AND TEMPERATURE 2. Describe the distribution of KMnO4 in each beaker after 30 minutes.

DIFFUSION AND TEMPERATURE 3. What is the effect of temperature on the rate of diffusion?  An

increase in temperature increases the rate of diffusion, because diffusion is dependent on the kinetic (thermal) energy of molecules.

DIFFUSION AND MOLECULAR SIZE 1. Where did you observe a color change, in the beaker or cellulose sac? How would you explain the color change?  Color

change occurred inside the sac.  This is due to the entry of IKI.

DIFFUSION AND MOLECULAR SIZE 2. Which substance has smaller molecules, starch or iodine?  Iodine

(IKI)  Because a change of color occurred inside the bag, indicating the entry of IKI into the bag.

DIFFUSION AND MOLECULAR SIZE 3. In what way is the cellulose / dialysis sac similar to the cell membrane  It

is semipermeable.

OSMOSIS AND THE RBC 1. Describe the shape of the RBC seen in thethree slides. Draw your observations.

DIFFUSION AND MOLECULAR SIZE 2. Which solution is HYPEROSMOTIC compared to the RBC?  5%

salt, because it has a higher solute concentration.  Solution in slide = 95% H2O  Solution in blood = 99.1% H2O

DIFFUSION AND MOLECULAR SIZE 3. Which solution is HYPOOSMOTIC compared to the RBC?  dH2O,

because it doesn’t have salt dissolved in it.  Solution in slide = 100% H2O  Solution in blood = 99.1% H2O

DIFFUSION AND MOLECULAR SIZE 4. Which solution is ISOOSMOTIC compared to the RBC?  0.9%

salt, because it has the same concentration of salt as the RBC.  Solution in slide = 99.1% H2O  Solution in blood = 99.1% H2O

MEASURING THE RATE OF OSMOSIS 20 18 16 14 12 10 8 6 4 2 0

DIFFUSION AND MOLECULAR SIZE 1. What is the relationship of osmosis with the concentration of sucrose  Direct

relationship

DIFFUSION AND MOLECULAR SIZE 2. Explain the results in sac # 5.  The

sac became lighter.  Water moved from the sac to the beaker due to the hyperosmoticity of the solution outside the sac.

END. Thank you.