the Concord Consortium
the National Science Foundation
This hands-on lab promotes understanding of exothermic processes in a chemical reaction that happens inside a see-through "baggie". It calls for mixing calcium chloride (commonly used as road de-icer), baking soda, and water. The bag acts as an isolated system, with the two chemicals placed in opposite corners. First, water is mixed only with the calcium chloride, which releases heat into the bag in an exothermic reaction. Next, the baking soda is allowed into the mix, which produces another chemical reaction. Students measure the temperatures with a sensor inside the bag. Adding the second ingredient produces carbon dioxide gas and calcium carbonate (antacid).
Editor's Note: See Related Materials for a similar lab from the American Chemical Society using the same raw ingredients in a non-closed container.
This item is part of the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The Concord Consortium develops deeply digital learning innovations for science, mathematics, and engineering.
6-8: 4D/M1a. All matter is made up of atoms, which are far too small to see directly through a microscope.
6-8: 4D/M3ab. Atoms and molecules are perpetually in motion. Increased temperature means greater average energy of motion, so most substances expand when heated.
6-8: 4D/M3cd. In solids, the atoms or molecules are closely locked in position and can only vibrate. In liquids, they have higher energy, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into a gas. In gases, the atoms or molecules have still more energy and are free of one another except during occasional collisions.
4E. Energy Transformations
6-8: 4E/M3. Thermal energy is transferred through a material by the collisions of atoms within the material. Over time, the thermal energy tends to spread out through a material and from one material to another if they are in contact. Thermal energy can also be transferred by means of currents in air, water, or other fluids. In addition, some thermal energy in all materials is transformed into light energy and radiated into the environment by electromagnetic waves; that light energy can be transformed back into thermal energy when the electromagnetic waves strike another material. As a result, a material tends to cool down unless some other form of energy is converted to thermal energy in the material.
6-8: 4E/M4. Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.
9-12: 4E/H4. Chemical energy is associated with the configuration of atoms in molecules that make up a substance. Some changes of configuration require a net input of energy whereas others cause a net release.
9. The Mathematical World
9B. Symbolic Relationships
6-8: 9B/M3. Graphs can show a variety of possible relationships between two variables. As one variable increases uniformly, the other may do one of the following: increase or decrease steadily, increase or decrease faster and faster, get closer and closer to some limiting value, reach some intermediate maximum or minimum, alternately increase and decrease, increase or decrease in steps, or do something different from any of these.
%0 Electronic Source %A Tiskus, Paul %D 2007 %T Concord Consortium: Baggie Chemistry %I The Concord Consortium %V 2013 %N 5 December 2013 %9 text/html %U http://itsisu.diy.concord.org/activities/1534
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