Overview/Annotation: / The rate at which a chemical reaction will proceed is directly related to the amount of surface area of the reactants present. Changing the amount of surface area of one of the reactants present will change the amount of time it takes for the reaction to occur. When too much acid builds in your stomach, it will tend to feel upset. Medicine such as, Alka-Seltzer, has been developed to relieve your upset stomach. This experiment will explore the rate at which an Alka-Seltzer tablet will cure an upset stomach based on the amount of surface area each tablet possess.
Content Standard(s): / SC(8) / 7. Describe states of matter based on kinetic energy of particles in matter.
Local/National Standards:
Primary Learning Objective(s): / The student will be able to determine if the rate of chemical reaction will be different in a crushed Alka-Seltzer Plus tablet than in a whole Alka-Seltzer Plus tablet.
Additional Learning Objective(s):
Approximate Duration of the Lesson: / 61 to 90 Minutes
Materials and Equipment: / Important Note: The total amount of materials needed will depend on the number of groups created (one group listed below).
- 2 250mL glass flasks
- 100mL Graduate Cylinder
- 50mL Graduate Cylinder
- Alka-Seltzer Plus Tablets
- White Vinegar
- Mortar and Pestle
- Acid/Base Dye Indicator “Bromocresol Green”
- Black Marker
- Gloves (all group members)
- Blue Plastic Spatula
- Medicine Droppers
- Stopwatches
- Labels
- Science Journal (optional)
Technology Resources Needed: / Computer/Internet
Printer
Background/Preparation: / Background Information for Teachers:
- This is a reaction between a base (Alka-Seltzer Plus) and an acid (vinegar).
- An acid/base indicator “Bromocresol Green” will be used to indicate when the simulated stomach is too acidic causing it to be upset.
- The solution will appear yellow after the addition of the acid (vinegar) indicating a presence of excess acid in the stomach.
- Alka-Seltzer tablets will be added to neutralize the excess acid within the stomach.
- When the acid is neutralized, the solution will turn back blue.
Students need a general understanding of chemical reaction prior to conducting this experiment.
Procedures/Activities: / The teacher will pass out the activity sheet entitled Think About It (experiment directions located at the top left of this handout) and discuss each section of the sheet. Each group will create a hypothesis prior to conducting the experiment.
- Obtain two 250ml glass flasks and label one as crushed Alka-Seltzer tablet and the other as whole Alka-Seltzer tablet.
- Using the 100ml graduate cylinder, place exactly 100ml of water into each glass flask.
- Using the medicine dropper, place 5 drops of dye indicator into each glass flask. If the water does not appear blue in color, place up to five more drops into each solution.
- Using the 50mL graduate cylinder, put 5mL of vinegar into each glass flask. The color of the water solution should now appear to be yellow indicating excess acid is presence.
- Using a mortar and pestle, grind one of the Alka-Seltzer tablets until well dispersed tiny grains are evident. Reads steps 6 and 7 before completing step 7.
- With the two flasks positioned side by side, place the crushed and the whole tablet into their labeled flasks.
- Using the stopwatch, time how long it takes the color to change back to blue for both Mr. Alka-Seltzer Plus reactions.
Which solution changed back to the blue color faster? Why?Which solution had the Alka-Seltzer with the highest surface area? Why?
Activity 2
Each group will use Microsoft Publisher or students could use the website to create a brochure or flyer explaining the following: (a) Why do we take Alka-Seltzer Plus? (b) Why should consumers purchase the Alka-Seltzer powder versus the Alka-Seltzer Plus tablet? (c) How do you know which form of Alka-Seltzer Plus has the highest level of surface area exposed. (d) Write a written reaction to the results of the experiment.
Attachments:**Some files will display in a new window. Others will prompt you to download. / Mr.Alka-SeltzerPlusLabRubric.doc
THINKABOUTIT-revised(1).pdf
Mr.Alka-SeltzerPlusBrochureRubric.doc
Assessment Strategies: / Informal Assessment
The teacher will monitor the activity and the students' responses to the questions listed in the section entitled Procedure Section of this lesson (clarification provided as needed). In addition, the teacher will evaluate the students using a rubric (see attachment). Both rubrics were created at Teachers may use ready-made rubric templates or customize their own personal rubric.
Extension: / Extension Activity 1
The students will go to and construct a presentation summarizing the lab experiment using a customized talking avatar. Teachers may go to the following website to view a quick and easy tutorial. Excellent website! If time permits, the teacher may video the presentations.
Extension Activity 2
The students will go to and construct a MR. Alaka-Seltzer Plus commercial using a customized talking avatar. Students get a opportunity to persuade consumers to purchase the Alka-Seltzer powder versus the Alka-Seltzer tablet.
Remediation: / To address various learning styles, the teacher may place at-risk students with proficient students. If students need additional assistance, the experiment may be repeated one-on-one or in small groups with the teacher.
Each area below is a direct link to general teaching strategies/classroom accommodations for students with identified learning and/or behavior problems such as: reading or math performance below grade level; test or classroom assignments/quizzes at a failing level; failure to complete assignments independently; difficulty with short-term memory, abstract concepts, staying on task, or following directions; poor peer interaction or temper tantrums, and other learning or behavior problems.
Presentation of Material / Environment
Time Demands / Materials
Attention / Using Groups and Peers
Assisting the Reluctant Starter / Dealing with Inappropriate Behavior
Be sure to check the student's IEP for specific accommodations.
Variations Submitted by ALEX Users: