Unit 2 Lesson 13 Aspirin Neutralization Laboratory

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Unit 2 Lesson 13 Aspirin Neutralization Laboratory Powered By Docstoc
					                          Grade 10 Applied Science – Unit Chemistry - Neutralization
                                Laboratory – Testing Aspirin
 Acetylsalicylic acid is commonly called Aspirin. It was first sold over 100 years ago to relieve pain, and it is
 one of the most commonly used drugs in the world. Aspirin has other uses including preventing blood clots.

 As its chemical name suggests Aspirin is acidic. This acidity can damage the stomach lining. To lessen this
 concern, some Aspirin contain other chemicals that reduce the acidity.

 Is the claim true? To measure this, you will use a base to perform a Neutralization Reaction on two types
 of Aspirin: (1) regular and (2) acid-reduced. You will use an acid-base indicator called phenolphthalein.
 The indicator will show when the reaction is complete. An acidic solution is neutralized when the next drop
 of base permanently changes the indicator from colourless to pink.

        To explore the idea of neutralization (e.g., action between an acid and a base)

        There will be no difference in the reactivity between different types of aspirin.

         Eye goggles
         50 mL graduated cylinder
         Two Erlenmeyer flasks
         Mortar and pestle
         Glass marking pen
         40 mL warm water
         Phenolphthalein indicator
         1 regular Aspirin tablet
         1 Extra-strength Asprin
         1 reduced-acidity Aspirin tablet
         NaOH solution

 RECALL – NaOH is corrosive. It can cause blindness. Use appropriate lab safety precautions.

        Add 20 mL of warm water to each flask
        Add five drops of indicator to each flask and swirl gently
        Using the mortar and pestle, crush the regular Aspirin tablet into a fine powder. Pour the crushed
         tablet into one of the flasks.
        Carefully wipe the mortar and pestle with the paper towel to remove any powder.
        Using the mortar and pestle, crush the reduced-acidity Aspirin table into a fine powder. Pour the
         crushed tablet into the other flask. Repeat for Extra-strength Aspirin
        Label the flask “Acid” “Extra-strength Aspirin” and “Reduced-Acidity” with the glass marking pen
        Add one drop of NaOH to each flask and record any colour changes.
        Continue adding one drop of NaOH to each flask. Record observations after each drop and record
         the number of drops of NaOH used
        Keep adding NaOH until colour changes stop. NOTE: One liquid may stop before the other liquid.

       How many drops of NaOH did it take to turn the regular Aspirin solution pink? Likewise, how many
        drops of NaOH did it take to turn the reduced-acidity Aspirin solution pink?
       What differences did you observe? Explain any differences.
       What factors may contribute to any inaccuracies in your experiment?
       How might reduced-acidity Aspirin be the better choice for someone prescribed Aspirin every day?

 LAB REPORT: Due ____________________________________

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