The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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The Dumas method is a protocol with methodology allowing the molecular weight of an unknown substance to be determined. The molecular weight of a compound is the sum of the atomic weights of the atoms which comprise the molecule. For instance, the molecular weight of water (H2O) is equal to the atomic weight of oxygen plus the atomic weights of two hydrogen atoms. Often, the Dumas method is used to determine the molecular weights of volatile organic substances that are liquids at room temperature.
Using the Dumas method, molecular weight is calculated by measuring the mass of a known volume of a vaporized liquid. The mass of the vapor produced is measured by condensing it into liquid. The Ideal Gas Law, PV=nRT, is then used to determine the volume of the gas, and from that, its density. In the Ideal Gas Law, P is pressure, V is the volume of gas in liters, n is the number of moles of the gas, R is the Ideal Gas Constant, and T is the temperature of the gas (on Kelvin scale). From the density of the substance, the molecular weight can be estimated. Once the molecular weight of a substance is known, estimates of its atomic composition, or which elements it is made from and in what proportions, can be made. The method was designed by a french chemist named Jean Baptiste André Dumas, after whom the procedure is now named. Even though, during the nineteenth century the science of chemistry was at a relatively early state, Dumas was able to show that the vapor densities of some organic compounds are directly proportional to their molecular weights.