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Changing pH Investigation I

Testing the pH of lemon juice

  1. Discuss an experimental procedure with your class. Before you begin your investigation make a prediction about the pH of water and how it will change as you add lemon juice.

  2. Create a spreadsheet to record the pH of the lemon juice (5 ml, 10 ml, 15 ml, 20 ml, 25 ml), baking soda (5 ml, 10 ml, 15 ml, 20 ml, 25 ml), and leaf (type 1, type 2, type 3) solutions that you will mix. Refer to Technical Hints to see how to create a spreadsheet.



  3. Obtain a clear plastic cup. Add 100 ml of water. Test the pH of the water by using the pH probe. Refer to Technical Hints to see how to use the DataLogger software to measure pH. Record your pH in your spreadsheet. Refer to Technical Hints to see how to transfer a spreadsheet.

  4. Place 5 ml of lemon juice into your cup. Retest and record the pH of your solution.

  5. Continue testing and recording pH after adding a 5 ml of lemon juice until you have added 25 ml of lemon juice to your water.

  6. Answer Question 1 in "Analysis".

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