Coacervates+lab+Procedure

=Materials:= Gelatin solution, 1% Arabic gum, 1% HCl, 0.1% methylene blue solution, .1% microscope slide cover slip mixing container plastic pipettes pH paper strips, 1-14 range

=Procedure:= 1. Using a pipette, add 3 ml of gelatin solution to a mixing container. Observe the solution, and record observations in the data table in your notebook. 2. Using the pipette labeled “gum Arabic sol,” add 1 ml of gum Arabic solution to the mixing container. Mix gently. Again observe the mixture, looking for coacervates in the mixing. 3. With a clean pipette draw up a sample of this mixture and place a drop on a microscope slide. Gently place a coverslip over the drop and observe it under the microscope. 4. Add 1 drop of HCl to the mixing container. Mix gently. Using the pH paper, measure the pH of the mixture and record it along with your observations of the mixture. 5. Continue to add HCl drop by drop until you begin to see coacervate droplets form as a white precipitate. Make sure that you continue to take pH readings and record them in your data table after every other drop. 6. Once coacervates have formed, draw up a sample of the mixture and place it on a microscope slide. Place a coverslip on the sample and observe it under the microscope. Note the structure, shape, and appearance of the coacervates. 7. Place a drop of methylene blue onto the slide and observe the coacervates. 8. After the coacervates have been observed in the mixture continue to add HCl until the droplets disappear. Record the pH.

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