Flinn’s Exploring Chemistry™—Chemical Bonding Package

Introduction

Connect principles of chemical bonding and the properties of chemicals with materials for an exciting set of five curriculum activities—two experiments, a demonstration and two POGIL™ activities. Completing these activities will give students a rare “backstage” look at the hidden world of molecules and compounds. Imagine the forces holding atoms together! Flinn’s Exploring Chemistry™ Chemical Bonding package provides a comprehensive, integrated set of lab activities to investigate the properties of ionic, covalent and metallic bonding and to explore the relationships between the properties of a material, its structure and chemical bonding.

Concepts

• Covalent bonding
• Lewis structures
• Polyatomic ions
• Ionic bonding
• Nomenclature
• VSEPR theory

Background

What’s in this Chemical Bonding Package?

Your package includes chemicals 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 activities may be found in Chemical Bonding, Volume 5 in the Flinn ChemTopic™ Labs series, which is provided in this 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. These activities truly are the best of the best!

The following activities may be performed in any order. One possible lesson plan is described.

• Super-Duper Polymer Gel (Demonstration)
• Lewis Structures and Molecular Geometry (Experiment)
• The Color of Chemistry (Experiment)
• Naming Ionic Compounds (POGIL Activity)
• Polyatomic Ions (POGIL Activity)

Experiment Overview

Super-Duper Polymer Gel
The relationship between bonding and structure is large enough to see if you use really big molecules! Wow students with this visually stunning demonstration of hydrogen bonding in a polymer. Combine a polymer with water to form a thick, viscous gel that appears to defy gravity when poured. Microscopic principles of bonding become macroscopic.

Lewis Structures and Molecular Geometry
Alhough they are invisible to the naked eye, single molecules exhibit a variety of shapes, or geometries, that influence their physical properties and chemical behavior. This guided-inquiry lab allows students to become proficient at drawing Lewis structures and use models to visualize their three-dimensional structures. Atoms may be combined and arranged in different ways according to their electronic structures. As a result, a variety of molecular shapes are possible.

The Color of Chemistry
What is your favorite color? Color affects our senses, our moods, even our learning. In this beautiful experiment, students investigate the interaction of a variety of dyes with a special multifiber test fabric containing strips of wool, acrylic, polyester, nylon, cotton and acetate. The brilliant color patterns produced by different dyes teach students about the chemical structures of dye and fabric molecules and the types of binding interactions between them.

Naming Ionic Compounds
Students will learn by doing as this process-oriented guided inquiry learning activity offers subtle instructions for students to name ionic compounds composed of main group and transition metal elements. At the activity’s completion, students will have a firm understanding of chemical nomenclature as it relates to ionic compounds.

Polyatomic Ions
Reinforce twin concepts of covalent versus ionic bonding with this learning activity. Polyatomic ions are groups of atoms linked through covalent bonds to form charged, multi-atom ions. This activity provides leading questions and hints to help your students become proficient at this learning goal.

Materials

Prelab Preparation

The Color of Chemistry

Preparation of Dye and Mordant Solutions
Directions are given for preparing 200 mL of each solution. Prepare two baths for each dye. Dye baths may be used continuously during the day by different class sections. Note: Indigo dye not included in this kit.

Alizarin Red: Dilute 25 mL of 1% alizarin red solution with 175 mL of distilled or deionized water in a 400-mL beaker. Place a boiling stone in the dye solution and heat to near boiling on a hot plate.

Aluminum Potassium Sulfate (Alum): Dissolve 0.7 g of alum [AlK(SO₄)₂•12H₂O] in 200 mL of distilled or deionized water in a 400-mL beaker. Add 0.4 g of calcium oxide and stir to dissolve. Place a boiling stone in the solution and heat to near boiling on a hot plate.

Congo Red: Dilute 70 mL of 0.1% congo red solution with 130 mL of distilled or deionized water in a 400-mL beaker. Add 2 g of sodium sulfate decahydrate (Na₂SO₄•10H₂O) and 1.5 g of anhydrous sodium carbonate (Na₂CO₃) and stir to dissolve. Place a boiling stone in the dye solution and heat to near boiling on a hot plate.

Crystal Violet: Dilute 10 mL of 1% crystal violet solution with 190 mL of distilled or deionized water in a 400-mL beaker. Place a boiling stone in the dye solution and heat to near boiling on a hot plate.

Malachite Green: Dilute 10 mL of 1% malachite green solution with 190 mL of distilled or deionized water. Place a boiling stone in the dye solution and heat to near boiling on a hot plate.

Methyl Orange: Dissolve 0.7 g of methyl orange in 200 mL of distilled or deionized water. Add 2.5 g of sodium sulfate decahydrate (Na₂SO₄•10H₂O) and 5 mL of 1 M sulfuric acid and stir to dissolve. Place a boiling stone in the dye solution heat to near boiling on a hot plate.