Identifying Acids and Bases Lab - Kathy Egbert | Library

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Class Period

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Case Scenario/Question:  Are common household cleaners usually acids or bases?

Before you collect the pH of the household samples, consider what you know about the cleaners and hypothesize about whether the item is an acid or a base.  Complete Column 2 with your predictions by entering either A (for acid) or B (for base) in the Table below.

Lab Rules Apply - No Goofing Around

Materials:  ph Meter or ph tape, beakers with samples

Procedure:  
1st - Collect the actual pH reading for each of the household samples provided to the class.  Enter your reading in Column 3 in the Table below. [#1 water is tap water, not distilled water.  Alcohol has been substituted for #7 Lime Away]
2nd - Using the pH scale in your textbook on page 43 or from the ppt slides, indicate whether your reading is an acid, base, or neutral by putting a mark in one of the 3 columns (#4, #5, or #6) respectively.
3rd - Use the same resource to determine the hydrogen cations concentration [H+].  Enter that information in Column 7 by using  " < " for a lower concentration and "  > " for a higher concentration.

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Complete the hypothesis by filling in the "then" half If the household cleaning product is an acid, then...

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Table: pH readings of common household cleaners [#1 water is tap water, not distilled water. Alcohol has been substituted for #7 Lime Away]

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What was the control in this experiment?

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Graph and Analyze your results 1) Complete the graph by adding the Y axis tick marks and filing in the label for the X axis; the title and the tested substances are already entered for you along the x axis 2) Using your pH data for the 12 household cleaners make a scatter plot graph

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Based on your results: Are household cleaners usually acids or bases? Support your claim by giving examples and the number of the products that are acids vs bases.

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Reflection: Tell me about the most interesting result you received and why you thought it was interesting. Use complete sentences.

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Review: What was the independent variable in this lab?

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Review: What was the dependent variable in this lab?

Clean up  - Everyone is responsible for clean-up
Be sure that your lab station is clean and all items used returned to their correct location.
Be sure to wipe down your lab station and discard any trash you have.