Investigating property definitions

Hydrophilic:

  1. Place a piece of each color fabric on a sheet protector.
  2. Use a pipette to add a drop of water to each of the fabric pieces.
  3. Record observations in data table below.

Color
Response to water
Hydrophilic

4. Mark yes in the bottom box for any of the fabrics that were hydrophilic.

Hydrophobic:

  1. Place a small amount of each chemical substance in a well of the well plate. Keep track of which well has what.
  2. Use a pipette to add 1-2 drops of water to each of chemical substance.
  3. Record observations in data table below.

Substance
Response to water
Hydrophilic

4. Mark yes in the bottom box for hydrophilic substances.

Application:

1) Make 2 lists below of substances that you come in contact with that are hydrophilic and those that are hydrophobic.

HydrophilicHydrophobic

pH:

  1. Fill 2 250mL beakers with 100mL of water.
  2. Label 1 beaker “1 drop” and the other “10 drops”.
  3. Record the pH of the water in the data table below under initial.
  4. Add 1 drop of hydrochloric acid (HCl) to the 1 drop beaker and stir with a stirring rod.
  5. Check the pH and record it under “After HCl”.
  6. Repeat steps 4–5 for the 10 drop beaker.
  7. Sprinkle baking soda (NaHCO3) into the 1 drop beaker. Then stir slowly. STOP when you see no more bubbles.
  8. Check and record the pH in the appropriate spot on the data table.
  9. Repeat steps7-8 for the 10 drop beaker.
  10. In the “how much” spaces on the data table record which beaker needed more baking soda.

Beaker / 1 drop / 10 drops
Initial pH
After HCl
After NaHCO3
How much?

11) How do the after HClpH values compare?

12 a) Compare the after baking soda pH values of the beakers.

b) Give a reason for your observation in a.

Molecular representations:

1 drop beaker2 drop beaker

pH of chemical substances:

  1. Place a teeny tiny amount of each chemical substance in a well of the well plate. Keep track of which well has what.
  2. Using a pipette, add water to the well until it is half full.
  3. Mix with a toothpick.
  4. Dip a pH strip in each well and record the pH in data table below.

Substance
pH
Acidic, basic, neutral?

5. Some, not all, substances require neutralization before disposal. Place each of the substances you tested in the appropriate column below.

Baking soda solutionVinegarNeither

Why does pH matter?

Liquid test:

  1. Label a 50mL beaker with the names of the liquids available for this lab.
  2. Place 25mL of liquid in its labeled beaker.
  3. One at a time, taking time to observe, add ____ drops of HCl to each liquid and stir with a stirring rod.
  4. Record observations in the table below.
  5. Clean up: Add a pipet full of baking soda solution to each beaker.
  6. Place paper towels in the beaker to soak up the liquid.
  7. Throw paper towel in garbage.
  8. Wipe out beaker with more wet paper towel.
  9. Use soap to wash the beaker.
  10. Rinse 7 times with tap, 2 times with distilled.
  11. Dry.

Liquid
Observations

Solid test:

  1. Use tape to label a box on the sheet protector for each of the solids available.
  2. One at a time, add 2-3 drops of HCl to each solid.
  3. Record observations in the data table.
  4. Clean up:Sprinkle baking soda on each of the solids until bubbling stops.
  5. Use a paper towel to wipe everything off the sheet into the garbage.
  6. Wipe the surface with a wet paper towel to remove all the solid bits.
  7. Use soapy water to clean the sheet protector.

Solid
Observations

Conclusions:

1) Summarize your findings with regard to the liquids and solids you tested.

2) Research: Think of an area of interest to you (environment, cooking, cosmetics, human body, other) & find out the role pH plays.