July 2005, ChemEd Conference, UBC, Vancouver, Canada Plop! Plop! Fizz! Fizz! Oh, the things chemistry teachers can do with AlkaSeltzer! Patricia Mason, PAEMST 2003 Delphi Community High School masonp@delphi.k12.in.us Judith Flint Baumwirt Granada Hills Charter High School jbaumwirt@ghchs.com July 2005, ChemEd Conference, UBC, Vancouver, Canada

Experiments and Activities Alka Seltzer Rainbow - ChemFax Demonstration (provided by Flinn Scientific) Alka Seltzer Rockets Buffering Ability of Alka Seltzer Tablets Buffer Balancing Acts - ChemFax Demonstration (provided by Flinn Scientific) Common Ion Effect on the Solubility of Alka Seltzer

Experiments and Activities Change in pH and Temperature as a Reaction Occurs Differentiating Liquids Decomposition of Effervescent Tablets Decomposition of Effervescent Tablets with Sample Data Analysis/Results Density Challenge Does a Gas Have Mass?

Experiments and Activities Effect of Particle Size on Rate of Reaction Demonstration Effect of pH on rate of reaction Effect of Temperature on Rate of Reaction Demonstration Rate of Reaction Lab - Combined Activities for Students Equilibrium and Rate Determining Step demonstrations

Experiments and Activities Micro Popper (provided by Flinn Scientific) Quantitative Determination of Sodium Bicarbonate in Alka Seltzer Second Quarter Laboratory Evaluation:  Analysis of Alka Seltzer (provided by Flinn Scientific) What Chemists Do: Identification and Analysis - White Powder Identification

Alka-Seltzer Rockets Factors affecting the rates of solution It is important to break tablets evenly into four quarters Only Fuji canisters provide a good seal (lid fits securely inside the canister) Inverted in the launcher Can be used test variables

Factors Affecting Rate of Reaction Effect of Temperature on Rate of Reaction Teacher demonstration Student activity Effect of Particle Size on Rate of Reaction Whole tablet Broken in half Quartered Coarsely ground Finely ground

Effect of pH on Rate of Reaction Complicated set-up Glass work done by teacher saves time Solutions available of various pH Each group uses water plus 2 others Water displacement technique Plotting data and analysis Comparison of rates with pH

Common Ion Effect Can be used as a discrepant event Why do the tablets dissolve at different rates and in varying amounts?

Monitoring Changes in pH and Temperature as Reaction Occurs Must use probeware for pH Temperature Tablets are added to room temperature water Data taken for 5 minutes Variables can be changed Number of tablets Division of tablets Amount of water Amount of agitation

Buffering Ability of Alka-Seltzer Tablets Macro-Demonstration Burets HCl and NaOH Universal indicator HCl with water HCl with tablet NaOH with tablet NaOH with water Can also use pH probes Micro-Activity Broken tablets (0.15g to 0.20 g samples) Well-plates Universal indicator Calibrate the micro-pipettes for drops

Does a Gas Have Mass? Can be used initially for introduction to Chemistry Can be used to demonstrate conservation of mass When a gas is produced is mass lost? Baggie provides a closed system

Differentiating Liquids Lab Good introductory lab activity Properties of Liquids Viscosity Density Solubility Detailed data recording and evaluation Inquiry section, if time permits

Equilibrium and Rate Determining Step Demo An entertaining student-centered activity Shows the progress of a reaction from reactants to a mixture of reactants and products Can visually recognize that the reaction is favored in the decompositon direction The “Slow step” is obvious in this demonstration

What Chemists Do – A Beginning Analysis Lab This is a good application of inquiry and the scientific method. May be useful as a beginning lab on analysis Students have three unknowns to determine so the lab requires some extended prep time.

Quantitative Determination of Sodium Bicarbonate AP Chemistry Stoichiometry Calculations Limiting Reactant Graphing Acid-base Solutions Decomposition