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Chapter Concepts:

Chapter 4: Chemical Dominoes
Chapter Challenge You are challenged to create a prototype of a “chemical-dominoes sequence” that can be sold by a toy company to10-15 year-old children. You are asked to demonstrate the product to company executives, as well as to explain the chemistry concepts behind each step. A detailed written explanation of the chemistry is also required.
Activity Summaries	Chemistry Principles
Activity 1: Alternative Pathways Students compare different ways of producing carbon dioxide gas to blow up a balloon that tips a lever. They brainstorm criteria for selecting which method might be best for using in the Chemical Dominoes apparatus. After an introduction to two chemical concepts (endothermic/exothermic changes, entropy increase/decrease) and drawings of arrangements of particles in different states (before/after), each student in the group becomes an expert in one of the carbon dioxide production methods.	Reactants, Products Endothermic & Exothermic Energy Entropy Engineering design process Covalent bond Ionic bond Excited state
Activity 2: Balancing Chemical Equations Students first learn to recognize whether a chemical equation is balanced. Then, they learn to balance simple chemical equations by an accounting method. Along the way, they practice identifying how many of a particular element there are in a formula, which involves reading parentheses and subscripts properly. They also balance the equation for Method 2 from the previous activity, prove that it’s balanced, and then design an experiment and demonstrate that mass is conserved when the reaction is run.	Conservation of matter Balancing chemical equations
Activity 3: How Much Gas is Produced? In this activity, students use pennies and a balance to explore the concept of a mole. They also learn dimensional analysis with “chemical dominoes.” The point of the activity, for students, is to be able to predict ahead of time how much baking soda will be necessary to use to make this happen. Then, after an empirical solution to the problem, they learn stoichiometry and test their “hypothesis.” Finally, they participate in a discussion of error analysis to query why the prediction and reality are so different.	Stoichiometry Dimensional analysis Mole Molar mass Prediction Error analysis STP
Activity 4: What Can Destroy a Metal? Students build a circuit to light the red LED using aluminum foil as wire. They then experimentally learn to turn off the circuit by destroying the aluminum using three “mystery” chemicals. By observing the effects of known chemicals on metals, they deduce the identity of the “mystery” chemicals. They practice writing and balancing oxidation-reduction reactions. In a short activity, students address the confusion between dissolving, melting, and reacting and learn to define the terms properly.	Metal-activity series Reactivity of metals Oxidation-reduction Balancing equations Half-reactions Dissolving/melting Acids
Activity 5: Producing and Harnessing Light Students view the spectrum of visible light by looking at an incandescent light through a diffraction grating. After seeing that “white” light is made of many colors, they view the red LED through the diffraction grating. They then determine the minimum operating voltages for a series of colors of LEDs, leading them to conclude that as the wavelength of light decreases, the voltage (energy) required to light the LED increases. Next, students determine which colors of light can cause a glow-in-the-dark toy to phosphoresce. They conclude that for the phosphorescence to occur, a minimum amount of light energy must be added.	Matter-energy interactions Emission spectroscopy Absorption spectroscopy Energy vs. wavelength Electromagnetic spectrum Visible light Fluorescence Conservation of energy Phosphorescence Excited state Ground state
Activity 6: Electrochemical Cells Students use their red LED to build a conductivity tester. After testing several solutions, they determine which solutions conduct electricity, and therefore contain electrolytes. Students then construct a zinc-copper battery and use the LED to determine in which direction electricity flows. Afterward, students are introduced to two ways to create more voltage (so they can light LEDs that require greater voltage): connecting batteries in series, and changing the relative concentrations of the zinc and copper ion solutions.	Enthalpy changes Endothermic Exothermic Effects of catalysts Bond energy Reaction diagrams Activation Energy Activated complex Spontaneous reaction
Activity 7: Reactions that Produce Heat Students interpret observations from a military “Meals, Ready-to-Eat” (MRE) package. They operate the MRE and make sense of their observations. They learn about factors that speed up reactions, including particle size and catalysts. Finally, they use Hess’s Law to determine whether changes are endothermic or exothermic, and how much heat energy the reactions require or give off.	Electrochemical cells Half-reactions Spontaneity Electrolytes Hess’s Law
Activity 8: Rubber Bands and Spontaneity Students experiment with a rubber band, stretched and unstretched, to learn about enthalpy and entropy. They then build models to explain the behavior of the rubber bands. They formalize ideas of enthalpy and entropy change, and relate these ideas back to other activities in this chapter.	Reaction driving forces System Surroundings Spontaneity Exothermic Endothermic Degree of disorder Gibbs free energy Polymers Monomers