Basic energy concepts are reviewed and introduced - defining energy, the difference between potential and kinetic energy, the difference between heat and temperature, identifying reactions as endothermic or exothermic, and measuring energy changes during chemical reactions (calorimetry). |
Simple demonstrations may be used to illustrate the difference between endothermic and exothermic reactions.
A simple experiment measuring temperature changes during phase changes can be useful in exploring the conversion between potential and kinetic energy, and the difference between heat and temperature.
Simple calorimetry experiments may be performed to allow students to measure energy changes during chemical reaction. Performing simple calorimetry early in the unit provides more practice for the students who will use this technique to calculate heats of reaction. |
Assignments are used to assess students' understanding of the concepts of forms of energy, endothermic and exothermic reactions, and calorimetry.
Student research assignments may be used to investigate reactions that are used to produce useful heat in our society. Research of hot and cold packs may be used to compare endothermic and exothermic reactions. In lieu of tranditional fomal reports students may present their findings in other formats, including web pages, videos, etc. Links to evaluation rubrics are provided in the "Evaluation" section.
Several "quick research" questions are also suggested.
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| Enthalpy is introduced. Other key concepts include heat of formation and Hess's Law. Enthalpy is related to the direction of chemical change, reaction spontaneity and the stability of compounds. The direction of chemicl change is a concept that is is later reinforced in the Equilibrium module. Potential energy curves are introduced which are further developed in the Kinetics module. |
Calorimetry may be used to determine the heat of reaction; measuring heat of solution is a simple and easy technique.
Hess's Law may be explored by laboratory experiments. If acids and bases are used, teacher supervision is required. |
Assigments emphasize the quantitative measurement of the heat of reaction using Hess's Law, bond enthalpies, and heats of formation obtained from thermochemical data tables |
