11 Diffusion, Osmosis Lab p. 91

  1. DIFFUSION OF POTASSIUM PERMANGANATE AS AFFECTED BY TEMPERATURE

    Diffusion review.
    Observe diffusion of KMnO4 at 3 temperatures.
    What is your hypothesis about the effect of temperature on rate of diffusion?

    Record changes at 10 minute intervals for 30 - 60 minutes.

  2. DIALYSIS

    Dialysis is the separation of solutes by means of their unequal diffusion through semipermeable membranes.

    1. Tie one dialysis tube; make sure it does not ;eak.
    2. Mix into the tube a stock solution of 5 ml each of 3 solutes:
    3. After about 1 hour, apply tests:
      • Iodine (I2KI) for starch,
      • Benedict's solution (in warm water bath) for glucose,
      • Silver nitrate (AgNO3) for NaCl.
    What is your hypothesis about particle size and rate of diffusion?
    Which molecule(s) should diffuse out of the tube?

  3. OSMOSIS p. 92

    Osmosis review

    • Hypertonic, isotonic, hypotonic environments:

    • Use sucrose in 1M and 2M concentrations (1M = 6.02 * 1023 molecules per liter).
    • Measure height of water in pipet in 10-minute intervals.
    • Hypothesis: will the water level rise or fall?

  4. COLLOID PROPERTIES AND BROWNIAN MOVEMENT p. 93

    SKIP

  5. SOL-GEL REVERSAL p. 94

    SKIP


Index Lab notes made Jul 09, 2010 by Peter Chen