One of two kinds of passive transport,
Diffusion can transport ions from higher concentration to lower concentration region without any other forces. -
A net movement of molecules in and out of cell membrane
Diffusion can be affected by the steepness of the concentration gradient.
Is the rate of diffusion influenced by the presence of second molecule?
Prediction: the rate of diffusion is influenced by the presence of second molecule.
Vernier computer interface
Vernier Conductivity Probe
three 18×150 mm test tubes with rack
1％, 5％, 10％ salt water
dialysis tubing, 2.5cm ×12 cm
Dropper pipet or Beral pipet.
Ring stand and utility clamp
1. Connect the Conductivity Probe to the computer interface, and run Logger. 2. Put beaker on the Ring stand and pour 400ml water into beaker. 3. get 1%, 5%, 10% salt water in to three dialysis tubes
( -Obtain 15 mL of 1%, 5% and 10% salt-water solutions in each tube. -Soak three dialysis tubes into beaker one by one, and tie one end of the dialysis tubes. -Use a Beral pipet, transfer 15 mL of the 1%, 5% and 10% salt water into the dialysis tube -Tie off the other end of tube.)
4. put a weak magnet into the bottom of beaker.
5. wait for 20 sec
6. record by logger pro for 120 sec for 3 times (1%, 5% and 10% salt water each) 7. observe and compare all the data
8. get conclusion
9. Put every thing back and trash all three-dialysis tube.
The more salt concentration, the higher rate of diffusion will have. 2.
my conclusion proved my prediction is right. Almost no difference. 3. 5% to 1% ≈4.819 10% + 1% ≈ 8.886
The diffusion rate of a molecule is influenced by the presence of a second molecule. I proved this by using different salt concentrations and showing the...
Please join StudyMode to read the full document