Chemical Education Today
Letters Thermodynamic Mysteries I would like to make a few comments on the Commentary “‘Mysteries’ of the First and Second Law of Thermodynamics” by Professor R. Battino (1). First I would like to state that I am in complete agreement with Professor Battino’s basic premise that efficient chemistry teaching has to be timely. There are three issues that I would like to comment on: 1. 1st paragraph, line 9, “...the work and heat effects...” I believe that a more accurate common description of work and heat would be “processes” or “modes of energy transfer” (both terms emphasizing their dynamic character), rather than “effects”. Work and heat are the temporary causes that produce, as persistent effects, the changes of some properties or state functions, such as volume and temperature, of the system of interest. 2. 8th paragraph, line 1 “...U, is frequently and inappropriately called the internal energy.” My opinion is that the attribute “internal” is appropriate, because this energy (except in specialized treatments, see ref 2) depends on variables internal to the system such as temperature and composition. This energy does not depend on the external or mechanical coordinates such as the position and orientation in a force field (for example the electrostatic or gravitational field) or the speed of translation and rotation,
that define the potential and kinetic, or external, or mechanical energies. 3. 6th paragraph, line 6, “The mystery, the ‘miracle’ if you will, is that somehow in our universe the sum of two inexact differentials results in an exact differential.” A discussion of this point cannot feature the concision that would be appropriate to a letter and is considered for a possible written account. Literature Cited 1. Battino, R. J. Chem. Educ. 2007, 84, 753–755. 2. Münster, A. Classical Thermodynamics; Wiley-Interscience: London, 1970; pp 238, 265, 307.
Supporting JCE Online Material
http://www.jce.divched.org/Journal/Issues/2009/Jan/abs31_2.html Abstract and keywords; Full text (HTML and PDF) with links to cited JCE article Bruno Lunelli Istituto per lo Studio dei Materiali Nanostrutturati CNR Sezione di Bologna 101 via P.Gobetti I-40129 Bologna, Italy;
[email protected] © Division of Chemical Education • www.JCE.DivCHED.org • Vol. 86 No. 1 January 2009 • Journal of Chemical Education
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