Chemistry: The Nature of Energy
http://www.mindbites.com/lesson/1303-chemistry-the-nature-of-energy Energy is the capacity to do work or transfer heat. Professor Yee introduces Thermochemistry, or the study of energy changes associated with a chemical system. He introduces Kinetic Energy (the energy associated with motion), Potential energy (which is stored energy), and internal energy (which is the sum of kinetic and potential energy). Internal energy is difficult to define in chemistry, as Potential energy is not always evident. However, in chemistry, often the change in energy is most important, and this can be defined as: (final energy - initial energy). Lastly, Professor Yee introduces two different units for measuring energy, Joules and Calories. Joules measure energy as work, with work being the energy that moves an object against a force. Work, in chemistry, is often PV work, or a gas expanding against external pressure. Calories measure heat, or the transfer of energy from one object to another by a change in temperature. 1 cal is equal to exactly 4.184 Joules, and is approximately 1/1000 of a food calorie. Taught by Professor Yee, this lesson was selected from a broader, comprehensive course, Chemistry. This course and others are available from Thinkwell, Inc. The full course can be found at http://www.thinkwell.com/student/product/chemistry. The full course covers atoms, molecules and ions, stoichiometry, reactions in aqueous solutions, gases, thermochemistry, Modern Atomic Theory, electron configurations, periodicity, chemical bonding, molecular geometry, bonding theory, oxidation-reduction reactions, condensed phases, solution properties, kinetics, acids and bases, organic reactions, thermodynamics, nuclear chemistry, metals, nonmetals, biochemistry, organic chemistry, and more." Gordon Yee is an associate professor of chemistry at Virginia Tech in Blacksburg, VA. He received his Ph.D. from Stanford University and completed postdoctoral work at DuPont. A widely published author, Professor Yee studies molecule-based magnetism.