Activity 3: Activity 3: Transport ProcessesTransport Processes

Postlab DiscussionPostlab Discussion

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR WEIGHT: Part 1WEIGHT: Part 1

HCl + NH4OH NH4Cl + H2O

What are formed upon the reaction of HCl What are formed upon the reaction of HCl and NH4OH?and NH4OH?

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR WEIGHT: Part 2WEIGHT: Part 2

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

MW:MW:

Congo red Congo red = 697= 697

KMnO4 KMnO4 = 158= 158

Methylene blueMethylene blue = 319 = 319

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR WEIGHT: Part 2WEIGHT: Part 2

2.2. How does molecular weight affect the How does molecular weight affect the rate of diffusion?rate of diffusion?

Rate of diffusion is inversely proportional to Rate of diffusion is inversely proportional to molecular weight.molecular weight.

DIFFUSION AND TEMPERATUREDIFFUSION AND TEMPERATURE

1.1. Why is KMnO4 used in this experiment?Why is KMnO4 used in this experiment?

IONS:IONS:

Potassium = K+Potassium = K+

Permanganate = MnO4-Permanganate = MnO4- Because it is a salt that easily dissolves in Because it is a salt that easily dissolves in

water.water. It dissolves in water to give deep purple It dissolves in water to give deep purple

solutions solutions

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

DIFFUSION AND TEMPERATUREDIFFUSION AND TEMPERATURE

DIFFUSION AND TEMPERATUREDIFFUSION AND TEMPERATURE

3. What is the effect of temperature on 3. What is the effect of temperature on the rate of diffusion?the rate of diffusion?

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

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

1. 1. Where did you observe a color change, Where did you observe a color change, in the beaker or cellulose sac? How in the beaker or cellulose sac? How would you explain the color change?would you explain the color change?

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

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

2. 2. Which substance has smaller molecules, Which substance has smaller molecules, starch or iodine?starch or iodine?

Iodine (IKI)Iodine (IKI)Because a change of color occurred inside Because a change of color occurred inside

the bag, indicating the entry of IKI into the the bag, indicating the entry of IKI into the bag.bag.

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

3. 3. In what way is the cellulose / dialysis sac In what way is the cellulose / dialysis sac similar to the cell membranesimilar to the cell membrane

It is semipermeable.It is semipermeable.

OSMOSIS AND THE RBCOSMOSIS AND THE RBC

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

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

2. Which solution is HYPEROSMOTIC 2. Which solution is HYPEROSMOTIC compared to the RBC?compared to the RBC?

5% salt, because it has a higher solute 5% salt, because it has a higher solute concentration.concentration.

Solution in slide Solution in slide = 95% H2O= 95% H2OSolution in blood Solution in blood = 99.1% H2O= 99.1% H2O

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

3. Which solution is HYPOOSMOTIC 3. Which solution is HYPOOSMOTIC compared to the RBC?compared to the RBC?

dH2O, because it doesn’t have salt dH2O, because it doesn’t have salt dissolved in it.dissolved in it.

Solution in slide Solution in slide = 100% H2O= 100% H2OSolution in blood Solution in blood = 99.1% H2O= 99.1% H2O

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

4. Which solution is ISOOSMOTIC 4. Which solution is ISOOSMOTIC compared to the RBC?compared to the RBC?

0.9% salt, because it has the same 0.9% salt, because it has the same concentration of salt as the RBC.concentration of salt as the RBC.

Solution in slide Solution in slide = 99.1% H2O= 99.1% H2OSolution in blood Solution in blood = 99.1% H2O= 99.1% H2O

MEASURING THE RATE OF MEASURING THE RATE OF OSMOSISOSMOSIS

0

2

4

6

8

10

12

14

16

18

20

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

1. 1. What is the relationship of osmosis with What is the relationship of osmosis with the concentration of sucrosethe concentration of sucrose

Direct relationshipDirect relationship

DIFFUSION AND MOLECULAR DIFFUSION AND MOLECULAR SIZESIZE

2. 2. Explain the results in sac # 5.Explain the results in sac # 5.

The sac became lighter.The sac became lighter.Water moved from the sac to the beaker Water moved from the sac to the beaker

due to the hyperosmoticity of the solution due to the hyperosmoticity of the solution outside the sac.outside the sac.

END.END.

Thank you.Thank you.