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 About Virtlab
Carl Spitzweg (1808-1885) "Der Alchemist"

 Virtlab Demonstration
Pietro Longhi (1701 - 1785) "The Alchymist"

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Thermodynamics Resources For Students And Teachers!

First and second laws of thermodynamics, conservation of energy, reversible expansion of a gas, adiabatic and isothermal expansion of a gas, Carnot cycle, entropy as q/T, thermal energy, Gibbs free energy.

What is Virtlab?

  • Virtlab is a laboratory manual that uses laboratory simulations to perform its experiments. Simulations are also available as electronic spreadsheets that you or your students can build and explore Our authors pioneered this approach and have refined it over many years. We are among the first educators in the world to integrate personal computers and science education.

  • Virtlab is divided into two sections. "Free Virtlab" shows you how the process works. "Full Virtlab" offers you our complete storyline. If you are uncertain about the value you will find in Virtlab then subscribe for one month at US$ 4.95. If you like what you see then extend your subscription for six months using the far more cost effective 6 month subscription of US$14.95.

Chapter 8 - Thermodynamics:

  • Exercise 8.1 - The First Law: Conservation of Energy: Imagine an ideal gas contained in a cylinder sealed at one end by a moveable piston that exerts just enough pressure to keep the gas from either expanding or compressing (not shown). If the external pressure is instantaneously reduced by some amount (say, 0.1 atm) the gas will expand to a new equilibrium volume and work will be performed by the gas on the piston. If the external pressure is reduced in two steps (of, say, 0.05 atm each) the work performed by the gas will be greater. If the steps become infinitely small and if the gas is in equilibrium at every step during its expansion, the gas will perform the maximum possible amount of work on its confining piston. Processes that are in equilibrium throughout their duration are called reversible processes. Exercise 8.1 explores the reversible and irreversible expansion of a gas under conditions when the gas is either thermally isolated from its environment (adiabatic expansion) or in thermal equilibrium with its environment (isothermal expansion). This exercise lays the groundwork for Exercise 8.2 -- an exploration of the Carnot Heat Engine and entropy. (Exercise 8.1 is part of "Free Virtlab".)

  • Exercise 8.2 - The Second Law: Direction: The steps described in Exercise 8.1 can be organized into a closed cycle called the Carnot Heat Engine (shown on the left). In this exercise students monitor the pressure, volume, temperature and transfers of thermal energy into and out of a gas as it cycles through this engine and discover that these thermal energy transfers (q) when divided by the absolute temperature of the environment (T) reveal a new state function of matter, q/T, called entropy. Students come to understand that, in chemistry, entropy is primarily a measure of the capacity of matter to hold thermal energy. It is a measure of the "looseness" of intramolecular bonds. (Exercise 8.2 is part of "Full Virtlab".)

  • Exercise 8.3 - Gibbs Free Energy: The Direction And Extent of A Reaction: The Carnot Cycle, Exercise 8.2, deals with ideal gases undergoing changes in pressure and volume. Most chemical reactions occur under conditions of constant pressure. Also, unlike ideal gases, chemical reactions involve intermolecular interactions that change intramolecular structure. Exercise 8.3 provides a brief introduction to the Gibbs Function and chemical thermodynamics.(Exercise 8.3 is part of "Full Virtlab".)

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Virtlab is based on the simulations and guided exercises found in N. Simonson & Company's pioneering text: Dynamic Models in Chemistry by Daniel E. Atkinson (University of California, Los Angeles, CA), Douglas C. Brower, and Ronald W. McClard (Reed College, Portland, OR). Laboratories are also under development for Dynamic Models in Physics (Volume I: Mechanics) by Frank Potter (University of California, Irvine, CA), and Charles W. Peck (California Institute of Technology, Pasadena, CA), and Dynamic Models in Biochemistry by Daniel E. Atkinson (University of California, Los Angeles, CA), Steven G. Clarke (University of California, Los Angeles, CA), and Douglas C. Rees (California Institute of Technology, Pasadena, CA)

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A new exercise Simple and Fractional Distillation now exists. Other recent simulations include explorations of stoichiometry (moles, mole fractions, limiting reagents), the Ideal Gas Law and the Equation of State, Charles Law, Boyles Law, Raoults Law, and acidic dissociation (including isoelectric points). Stoichiometry is an important subject and Charle's law, Boyle's Law, together with Raoult's Law and acid base titrations are important matters. Daltons Law of Partial Pressures, sometimes called Dalton's Law of partial pressures play crucial roles can help in understanding fractional distillation. dalton's law of partial pressures (daltons law of partial pressures) should be understood by all students. Along with fractional distillation. Will you be ready for acid base titration or acid base titrations. We hope so. And don't forget or stoichiometry exercises.