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Properties of Matter: Investigation 4 –










This Investigation is designed to:

  • promote your exploration of the property of pH,
  • introduce you to the Determination of pH Using pH paper procedure,
  • provide you with an opportunity to discover that compounds can be acidic, basic, or neutral, and
  • encourage your analysis of the relationship between elemental composition, compounds, and pH.


Student Preparation includes gathering the following materials.

Note: The materials are listed in your SDR. They are also listed below for your reference.

  • (16) pH strips
  • (5) weigh dishes
  • (5) empty 400 ml beakers
  • (3) empty 100 ml beakers
  • (1) 100 ml graduated cylinder
  • (8) 2cm pieces of masking tape
  • (1) pH chart
  • (1) triple beam balance
  • (1) marker
  • (1) liter pitcher filled with 1000 ml of water
  • (1) pair of goggles for each student
  • (1) pair of vinyl gloves for each student
  • (1) glass stir rod


  • Reflect on the PreLab video as they move through the procedural steps.
  • Explain to students that during the Experiment, every procedural step is important. If one step is skipped, data can become invalid. To help students keep on track, direct them to read each step thoroughly, complete the step, then check it off (Read it – Do it – Check it off).
  • Direct students to complete procedural steps in their SDRs.
  1. Test the pH of the liquid compounds.
    1. Locate each liquid compound at the distribution center.
    2. Use a graduated cylinder to add 50 ml of a liquid compound to an empty 100 ml beaker.
    3. Use the tape and marker to label the beaker.
    4. Use the pH indicator strip to determine pH. You may also wish to refer to the Determination of pH procedure.
    5. Record: Write your results in Table A.


  1. Test the pH of the solid compounds. Solids must be made into solutions in order for the pH strips to be activated.
    1. Test the pH of the water with a pH indicator strip.
    2. Record: Write your results in Table A.
    3. Create a solution.

    – Pour 100 ml of water into a 400 ml beaker.

    – Add 10 grams of the solid compound.

    – You may wish to refer to the Triple Beam Balance Equilibration, Triple Beam Balance Use and Operation, and Measuring Mass Using a Weigh Dish or Beaker procedures.

    – Use tape and a marker to label the beaker.

    – Stir the solution for several minutes with a glass stir rod until the solid is completed dissolved.

        1. Dip a pH indicator strip into one of the beakers for 1 or 2 seconds.
        2. Remove the strip after 2 seconds and compare the colors to the indicator on the pH strip container.
        3. Record: Write your results in Table A.


      CLEAN UP

      Help your group return materials and clean the lab bench after you are finished with the experiment.