Gesser Applied Chemistry A Textbook for Engineers and Technologists Second Edition O. Gesser Chemistry Department Chemistry Department University of Manitoba University of Manitoba Winnipeg, Manitoba, Canada Winnipeg, Manitoba, Canada ISBN 978-1-4614-4261-5 ISBN 978-1-4614-4262-2 (eBook) DOI 10.1007/978-1-4614-4262-2 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012947030 # Springer Science+Business Media New York 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work.
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Roussak: In memory of my father, Roussak Vladimir Alexandrovich, a smart mining engineer, my best friend and teacher. Gesser: To Esther, Isaac, Sarah and Avi. Preface to the Second Edition The first edition of this book appeared 10 years ago. This book is the result of teaching in the Applied Chemistry (Dr.
Gesser, the Chemistry 2240 course) as well as in the Water Quality Analysis for Civil Engineers (Dr. Roussak, the CHEM 2560 course) to second year engineering students for many years at the University of Manitoba (Winnipeg, Manitoba, Canada). Much has transpired in science during this period and that includes applied chemistry. The major change in this new edition that becomes obvious is the addition of several (eight) experiments to accompany the book and the course for which it was intended.
A new solutions manual is also a valuable asset to the second edition of the book. Chemistry is primarily an experimental science and the performance of a few experiments to accompany the text was long considered while the course was taught. The choice of experiments we include was determined by the equipment that is usually available (with one or two possible exceptions) and by the expected usefulness of these experiments to the student, who will eventually become a practicing professional, and to the cost that is involved in student time. We welcome any reasonable and inexpensive additional experiments to introduce for the next edition of our book and topics to include in the next edition.
Winnipeg, Manitoba, Canada O. Gesser vii Preface to the First Edition This book is the result of teaching a one semester course in applied chemistry (Chemistry 224) to second year engineering students for over 15 years. The contents of the course evolved as the interests and needs of both the students and the engineering faculty changed. All the students had at least one semester of introductory chemistry and it has been assumed in this text that the students have been exposed to thermodynamics, chemical kinetics, solution equilibrium, and organic chemistry.
These topics must be discussed either before starting the applied subjects or developed as required if the students are not familiar with these prerequisites. Engineering students often ask “Why is another chemistry course required for non-chemical engineers?” There are many answers to this question but foremost is that the professional engineer must know when to consult a chemist and be able to communicate with him. When this is not done, the consequences can be disastrous due to faulty design, poor choice of materials, or inadequate safety factors. Examples of blunders abound and only a few will be described in an attempt to convince the student to take the subject matter seriously.
The Challenger space shuttle disaster which occurred in January 1986 was attributed to the cold overnight weather which had hardened the O-rings on the booster rockets while the space craft sat on the launchpad. During flight, the O-ring seals failed, causing fuel to leak out and ignite. The use of a material with a lower glass transition temperature (Tg) could have prevented the disaster. A similar problem may exist in automatic transmissions used in vehicles.
The use of silicone rubber O-rings instead of neoprene may add to the cost of the transmission but this would be more than compensated for by an improved and more reliable performance at 40 C where neoprene begins to harden; whereas the silicone rubber is still flexible. A new asphalt product from Europe incorporates the slow release of calcium chloride (CaCl2) to prevent icing on roads and bridges. Predictably, this would have little use in Winnipeg, Canada, where 40 C is not uncommon in winter. The heavy water plant at Glace Bay, Nova Scotia, was designed to extract D2O from sea water.
The corrosion of the plant eventually delayed production and the redesign and use of more appropri- ate materials added millions to the cost of the plant. A chemistry colleague examined his refrigerator which failed after less than 10 years of use. He noted that a compressor coil made of copper was soldered to an expansion tube made of iron. Condensing water had corroded the—guess what?—iron tube.
Was this an example of designed obsolescence or sheer stupidity. One wonders, since the savings by using iron instead of copper is a few cents and the company is a well-known prominent world manufacturer of electrical appliances and equipment. With the energy problems now facing our industry and the resulting economic problems, the engineer will be required to make judgments which can alter the cost-benefit ratio for his employer. ix x Preface to the First Edition One must realize that perpetual motion is impossible even though the US Supreme Court has ruled that a patent should be granted for a device which the Patent Office considers to be a Perpetual Motion Machine.
An example of this type of proposal appeared in a local newspaper which described an invention for a car which ran on water. This is accomplished by a battery which is initially used to electrolyze water to produce H2 and O2 that is then fed into a fuel cell which drives an electrical motor that propels the car. While the car is moving, an alternator driven by the automobile’s motion charges the battery. Thus, the only consumable item is water.
This is an excellent example of perpetual motion. A similar invention of an automobile powered by an air engine has been described. A compressed air cylinder powers an engine which drives the automobile. A compressor which is run by the moving car recompresses the gas into a second cylinder which is used when the first cylinder is empty.
Such perpetual motion systems will abound and the public must be made aware of the pitfalls. Have you heard of the Magnatron? Using 17 oz of deuterium (from heavy water) and 1.5 oz of gallium will allow you to drive an engine 110,000 miles at a cost of $110. Are you skeptical? You should be, because it is an example of the well-known Computer GIGO Principle (meaning garbage in ¼ garbage out). An engineer responsible for the application of a thin film of a liquid adhesive to a plastic was experiencing problems.
Bubbles were being formed which disrupted the even smooth adhesive coat. The answer was found in the dissolved gases since air at high pressure was used to force the adhesive out of the spreading nozzle. The engineer did not believe that the air was actually soluble in the hexane used to dissolve the glue. When helium was used instead of air, no bubbles formed because of the lower solubility of He compared to O2 and N2 in the solvent.
Everything is soluble in all solvents, only the extent of solution varies from non-detectable (by present methods of measurement) to completely soluble. The same principle applies to the permeability of one substance through another. An aluminum tank car exploded when the broken dome’s door hinge was being welded. The tank car, which had been used to carry fertilizer (aqueous ammonium nitrate and urea), was washed and cleaned with water—so why had it exploded? Dilute ammonium hydroxide is more corrosive to aluminum than the concentrated solution.
Hence, the reaction 3NH4 OH þ Al ! AlðOHÞ3 þ 3NH3 þ 1:5H2 produced hydrogen which exploded when the welding arc ignited the H2/O2 mixture. The broad explosive range of hydrogen in air makes it a dangerous gas when confined. Batteries are often used as a back-up power source for relays and, hence, stand idle for long periods. To keep them ready for use they are continuously charged.
However, they are known to explode occasionally when they are switched into service because of the excess hydrogen produced due to overcharging. This can be avoided by either catalyzing the recombination of the H2 and O2 to form water 2H2 þ O2 ! 2H2 O by a nickel, platinum, or palladium catalyst in the battery caps, or by keeping the charging current equal to the inherent discharge rate which is about 1% per month for the lead-acid battery. It has recently been shown that the flaming disaster of the Hindenburg Zeppelin in 1937, in which 36 lives were lost, may have been caused by static electricity igniting the outer fabric. This was shown to contain an iron oxide pigment and reflecting powdered aluminum.
Such a combination, known as a thermite mixture, results in the highly exothermic Gouldshmidt reaction (first reported in 1898): Fe2 O þ 2A1 ! A12 O þ 2Fe AH0 ¼ 852 kJ=mol of Fe2 O Preface to the First Edition xi In the early days of the railway, rails were welded with the molten iron formed in this reaction. The combination of powdered aluminum and a metal oxide has been used as a rocket fuel and evidence has been obtained to indicate that after the disaster the Germans replaced the aluminum by bronze which does not react with metal oxides. Thus, the bad reputation hydrogen has had as a result of the accident is undeserved and the resulting limiting use of the airship was due to faulty chemistry and could have been avoided. The original design and structure of the Statue of Liberty, built about 100 years ago, took into account the need to avoid using different metals in direct contact with each other.
However, the salt sea spray penetrated the structure and corroded the iron frame which supported the outer copper shell. Chloride ions catalyzed the corrosion of iron. The use of brass in a steam line valve resulted in corrosion and the formation of a green solid product. The architect was apparently unaware of the standard practice to use amines such as morpholine as a corrosion inhibitor for steam lines.
Amines react with copper in the brass at high temperatures in the presence of oxygen to form copper-amine complexes similar to the dark blue copper ammonium complex, Cu(NH3)J+. Numbers are a fundamental component of measurements and of the physical properties of materials. However, numbers without units are meaningless.