1 Lesson Plan By Gayle Crane, Chemistry and Sharon Lantz, Technology Modified from Lab developed by Don Miller and Gordon Parker at University of Michigan - Dearborn. Lesson Title: Plop, plop, fizz, fizz – Let’s see how much relief there is! (Determination of the amount of a chemical substance) Grade level: 9-12 Curriculum Areas Math Science Technology Objectives of Lesson understand the concepts of neutralization become familiar with the technique of titration Colorado Content Standards: Mathematics: I. DEVELOP NUMBER SENSE Students make measurements II. USE ALGEBRAIC METHODS Students construct data tables of observations and measurements. Science: I. PROCESSES OF SCIENTIFIC INVESTIGATION Students practice the scientific method. Students identify sources of error in an experiment. II. PHYSICAL SCIENCE 2.3 Students observe and measure physical interactions of matter. VI. SCIENCE AS A PARTICULAR WAY OF KNOWING Students learn about refining a hypothesis based on an accumulation of data over time. Technology Standards: III. TECHNOLOGY PRODUCTIVITY TOOLS o Students use technology tools to enhance learning, increase productivity, and promote creativity. o Students use productivity tools to collaborate in constructing technologyenhanced models, prepare publications, and produce other creative works. V. TECHNOLOGY RESEARCH TOOLS o Students use technology to locate, evaluate, and collect information from a variety of sources. o Students use technology tools to process data and report results. VI. TECHNOLOGY PROBLEM-SOLVING AND DECISION-MAKING TOOLS o Students use technology resources for solving problems and making Red Rocks Community College 2 informed decisions Materials: Tums, Rolaids, Milk of Magnesia Mortar and Pestle Weighing boats methyl orange solution hydrochloric acid Sheets of white paper Burets 3 125-mL Erlenmeyer flasks Funnels Handouts o Plop Table o Calculations/Question Sheet o “Acids and Bases” information sheet o Acid/Base Properties of Household Chemicals worksheet Technology Connection: Computers Printer Projection Device Publisher Digital Camera Excel Internet Teacher Background: In this lab, we will analyze the effectiveness of common preparations such as TUMS, Rolaids, and Milk of Magnesia in neutralizing the excess hydrochloric acid in your stomach. We will determine which product has the greatest acid neutralizing power per unit of cost. The active ingredient in an antacid is a base. A base is the opposite of an acid. When brought into contact with an acid both lose their characteristic properties, i.e. they are neutralized. The common bases used in antactid tablets are aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2, calcium hydroxide (Ca(OH)2 or some combination of these. Although each will neutralize stomach acid, excessive use is not recommended. Aluminum hydroxide can cause constipation, magnesium hydroxide also functions as a laxative, and calcium hydroxide can stimulate extra acid production in the stomach to replace that which has been neutralized. Each of these antacids contains a chemical which reacts with the acid in your stomach, neutralizing it and reducing the excess acidity. We will add acid to the material of these preparations, and by measuring the amount of acid which is neutralized by the prescribed dosage, compare their capacities for acid neutralization. The chemical technique of neutralizing a chemical with a measured quantity of another chemical is known as titration. Your instructor will explain the concepts of titration, pH and indicators and will demonstrate the techniques involved. Then, you can carry out the procedures for the Red Rocks Community College 3 antacid preparation assigned to your group. We will compare results after you have finished. Take care to carry out your measurements with precision. Lesson Procedures: In the Classroom: Before the lab section of the lesson, the teacher should give a presentation on Acids and Bases. Teacher can refer to the “Acids and Bases” information sheet. Pass our the Acid/Base Properties of Household Chemicals worksheet and Blue and Red Litmus paper for students to take home and test different substances. Investigation Part I (In the Chemistry Lab) Divide into Groups; Assign one person in the group the job of taking digital pictures of each step. (rotate this job) 1. Determine the mass of the recommended dosage of the antacid using the balance. name of antacid_______________________ mass of prescribed dosage_______________grams (1) Record this value in the plop table. 2. Make a solution of the antacid in water. First, grind the antacid using a mortar and pestle until only a fine powder remains. Carefully measure 100 mL of distilled water in a graduated cylinder. Wash the antacid powder from the mortar and pestle into a 250 mL flask with the 100 mL of water. You should now have a uniform slurry with no chunks of antacid in the solution. Be sure to get all of the antacid from the mortar and pestle with a small amount of distilled water from a wash bottle. 3. Add 10 drops of methyl orange solution to the flask. Methyl orange is a pH indicator which is a yellow color in basic solutions (here pH greater than 4.4) and is red in acid solutions (here pH less than 3.1). This will allow you to determine when you have reached the end point (i.e. the antacid has neutralized as much acid as it can). 4. Carefully fill the buret with 1 M hydrochloric acid. (M, molarity, is a measure of the acid strength.) Run a few drops of acid into a spare beaker by opening the stopcock, and discarding the acid in the sink, washing it down the drain with water. Then fill the buret tip past the stopcock. Be certain that there are not air bubbles in the buret. 5. Read the level of acid in the buret. Read the volume, using the lower part of the meniscus, as accurately as possible, estimating between the closest adjacent lines to hundredths of the milliliter. initial level______________mL (2) Red Rocks Community College 4 6. Place a sheet of white paper under the flask to more easily observe the color of the contents. Carefully and slowly open the stopcock on the buret and add acid to the flask while constantly stirring to mix the contents. Close the stopcock periodically and swirl the flask. As you approach the end point, (the point at which all of the acid has been neutralized) each drop of acid will turn the solution purple, but after swirling it will return to green. At this point, add acid only one drop at a time. Continue to add acid, drop by drop, swirling the flask after each drop is added. When the purple color persists for one minute after swirling and an additional drop causes no deepening of the color, you have reached the end point. That is, all the antacid chemical has been used up, and the last drop of acid made the contents of the flask permanently acid. Record the final level of acid in the buret. final level_______________mL (3) 7. Complete the Calculations and Question worksheet Now move to the Computer Lab Each person in the group will have a different assignment o Assignment #1: Using Inspiration, develop a concept map of the lab. Use your imagination. The pics from the camera can be used. o Assignment #2 and #3: Using Publisher, develop a flyer to advertise which antacid is the best. o Assignment #4: Using Excel, graph the results from the Plop Table. Include Appropriate graphics. Assessment: Plop Table Calculations/Question Sheet Inspiration concept map Publisher Flyer Web Sites: About Chemistry o http://chemistry.about.com/cs/a.htm http://www.teach-nology.com/teachers/lesson_plans/science/chemistry/reactions/ Chemistry Lesson Plans o http://www.chemsoc.org/links/Category.cfm?cattype=O Red Rocks Community College 5 o http://www.lessonplanspage.com/ScienceFoodChemistry-AcidBase35.htm Acids and Bases o http://www.visionlearning.com/library/moduleviewer.php?mid=58 Alternate version of the lab on the web o http://www.geocities.com/CapeCanaveral/Hall/1410/lab-C-10.html o http://www.chem.latech.edu/~deddy/chem104/104Antacid.html o http://antoine.frostburg.edu/chem/senese/101/acidbase/faq/antacidtitration.shtml Version of this lab without costly burets o http://www.woodrow.org/teachers/chemistry/institutes/1986/exp24.html Technology Integration Lesson Plan o http://www.nisd.net/secww/science/ScienceFinalProjects/Newman/Technology%20Integration%20Lesson%20Plan.pdf Red Rocks Community College