Introduction
Everything you need to plan your curriculum, prepare labs, and teach stoichiometry! You get a beautiful experiment with silver crystals, two demonstrations, as well as a POGIL™ activity. Build vital connections for success in chemistry by making sure students understand and can apply the mole concept. Understanding the mole concept makes it possible to analyze compounds and determine their formulas—the composition of matter. Applying the concept makes it possible to relate the amounts of chemicals consumed and produced in a chemical reaction—the properties of matter. The purpose of Flinn’s Exploring Chemistry™ Molar Relationships and Stoichiometry Package is to provide a comprehensive, integrated set of laboratory activities to accomplish the learning objectives for this vital unit in your curriculum.
Concepts
- Mole ratio
- Stoichiometry
- Solubility rules
- Chemical formulas
- Single replacement reaction
- Limiting reactant
- Balanced chemical equation
- Double replacement reaction
- Excess reactant
Background
What’s in this Molar Relationships and Stoichiometry Package?
Your package includes chemcials and specialty equipment to perform the lab and learning activities listed. Quantities of chemicals are sufficient for three classes of 30 students working in pairs! Instructions for all lab activities may be found in Molar Relationships and Stoichiometry, Volume 7 in the Flinn ChemTopic™ Labs series, which is included in the package. Student handouts for each activity may be reproduced for classroom use. Comprehensive instructions and teacher notes, with real sample data and answers to all questions, are also provided for each activity. All of the lab activities were created under the direction of the Flinn Scientific Curriculum Advisory Board of master teachers, and then tested and retested to optimize safety and success. The following activities may be performed in any order. One possible lesson plan is described.
- Stoichiometry and Solubility—Mole Ratios and Chemical Formulas (Demonstration)
- Mole Ratios—Copper and Silver Nitrate (Experiment)
- Limiting and Excess Reactants (POGIL Activity)
- Stoichiometry Balloon Races (Demonstration)
Experiment Overview
Stoichiometry and Solubility
Pictures are worth a thousand words, and the “Stoichiometry and Solubility” demonstration paints a perfect picture to visualize mole ratios in precipitation reactions. The height of precipitate forms a virtual or visual graph to determine the optimum mole ratio for the formation of precipitates in double replacement reactions. Use the information to predict the chemical formulas of the products.
Mole Ratios
Chemistry experiments don’t get more beautiful than the “Mole Ratios” lab! Crystallize the mole concept for students with shiny silver crystals growing on a copper wire in a blue solution. Students determine the number of moles of silver produced in the reaction of copper with silver nitrate and use the resulting mole ratio to write the balanced chemical equation for the reaction. Accurate results will have students doing more stoichiometry calculations to see how much their silver is worth!
Limiting and Excess Reactants
Take the mole ratio concept to the next, higher level with this great POGIL™ activity. Cooperative learning is ideal for developing advanced reasoning skills.
Stoichiometry Balloon Races
Wrap up the unit and have fun doing the “Stoichiometry Balloon Races” demonstration. Compare the amount of carbon dioxide filling up various balloons when acetic acid reacts with sodium bicarbonate to identify limiting and excess reactants.
Materials
Stoichiometry and Solubility
Copper(II) chloride solution, CuCl2, 0.05 M, 1 L
Iron(III) nitrate solution, Fe(NO3)3, 0.1 M, 1 L
Sodium hydroxide solution, NaOH, 0.1 M, 1 L
Sodium phosphate solution, Na3PO4, 0.05 1 M, 1 L
Mole Ratios
Acetone, CH3COCH3, 500 mL
Copper wire, Cu, 18-gauge, 13.7 m
Nitric acid solution, HNO3, 3 M, 25 mL
Silver nitrate, AgNO3, 70 g
Stoichiometry Balloon Races
Acetic acid solution, CH3CO2H, 1 M, 600 mL
Sodium bicarbonate, NaHCO3, 50 g
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