A Chemical Explanation

These opinions, that he expressed freely, cannot have endeared him to his colleagues in the medical profession and with one exception he never held a position at any of the many universities he visited. In 1526, he was appointed professor of medicine at Basel where he shocked the other professors by lecturing in German and not in Latin as custom required. Even worse, in the presence of his students he threw the revered books of the classic medical authors into the fire to demonstrate his complete break with the teachings that had dominated medicine for almost 2000 years. Characteristically enough, he soon found himself in acrimonious conflict with one of the councillors of the city over fees for medical services, and he resumed his incessant travelling. 

Undoubtedly, this theory was influenced by the interest of Paracelsus in alchemy, even if, like Rhazes and Avicenna, he was primarily fascinated by 

If Paracelsus can be seen as the pioneer of iatrochemistry, the Flemish aristocrat Johann Baptista van Helmont is its most famous protagonist. At the same time they were as different as could be. Paracelsus was uncouth and aggressive, 

In spite of all these unfounded speculations, we must not forget that van Helmont also made important chemical discoveries. For instance, he described the formation of what he called gas sylvestre (carbon dioxide) as the result of the burning of charcoal and the fermentation of must. He also coined the term gas as distinct from air and water vapor. Johann van Helmont was fascinated by ferments and fermentation and he believed that all processes in the organism were caused by ferments that converted food into living flesh in six steps. 

Franz de le Boe, called Sylvius (1614-1672) had all the personal qualities required of a successful clinician and teacher, that both Paracelsus and van Helmont so obviously lacked. He was bom in Hanau in Hesse, got his medical degree in Basel and was appointed professor of medicine at the University of Leyden in 1658. Here he reformed the medical education and introduced systematic clinical training of the students by demonstrations of patients in the wards, following teaching principles first developed in Italy. 

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Many metal objects are vulnerable to damage from corrosion. A famous example is the Statue of Liberty. Research the history of the effects of corrosion on the Statue of Liberty. Give a chemical explanation for the processes involved. Describe the steps taken to solve the problem and the chemical reasons for these steps. 

Cocaine is no stranger to us. We are very much aware of the abuse of this once helpful drug and the dangers not only to the psyche but also to the very existence of a body. The following is a chemical explanation of some of the features of cocaine preparation and use. 

He sought a chemical explanation of the problem of why crops responded differently to fermentation. After finding out part of the chemical conversion that occurred in leaf tobacco during fermentation, he sought a catalyst to accelerate and improve this process. The first indication for the presence of alkaloid transformation products in the fermented leaves was... 

From what you learned in Unit 3 about solutions and water treatment, do you think there could be other chemical-based solutions to this problem in the future Give a chemical explanation of how the leachates might be contained, if such processing were possible. 

The model provides a chemical explanation for charge buildup on variable-charge surfaces as salt concentrations are increased in solution. The explanation is that the activities of both base, MOH, and acid, HX, are increased by the addition... 

Give a chemical explanation for each of the following (a) Calcium metal is added to a sulfuric acid solution. Hydrogen gas is generated. After a few minutes, the reaction slows down and eventually stops even though none of the reactants is used up. Explain, (b) In the activity series, aluminum is above hydro-... 

However, believers in a chemical explanation were in the minority up into the twentieth century. Berzelius did not refer to Faraday s paper of 1834 (8), but we should. It was an excellent study... 

The demonstration, in 1919, that sunlight helped cure rickets—a childhood disease characterized by poor bone growth—began a search for a chemical explanation. 

Effect of pH on titration curve. Repeat the calculations of Problem 13-24 for pH = 7.00. Sketch the two titration curves on one graph and give a chemical explanation for the difference between the two curves. 

Second, chemistry is an intellectual enterprise, a way of explaining our material world. When Rosenberg and his coworkers saw that cell division in the bacteria had ceased, they systematically looked for the chemical substance that caused it to cease. They sought a chemical explanation for the occurrence. 

The demonstration, in 1919, that sunlight helped cure rickets—a childhood disease characterized by poor bone growth— began a search for a chemical explanation. Subsequent investigations showed that D vitamins were involved, and eventually it became known that one of several D vitamins, called vitamin D3, is the curative factor. Vitamin D3 is formed in the skin from 7-dehydrocholesterol by two reactions. In the first reaction (below). 

It has been thought that the rate acceleration is caused by generation of new active sites during this period A chemical explanation (15,16). It has also been speculated that a physical factor such as catalyst fragmentation could be rate limiting. 

Green, F. J. Polychromasia of Cresyl Violet dyes a chemical explanation of variations in pre-World War II products. Stain Technol. 1966, 41, 223-228. 

The thermodynamic approach does not provide a chemical explanation for the cluster-size dependence. Such explanation is provided when taking into account differences in the activation energy between different active sites present in clusters (corners, edges, and terraces), for which the ratio depends on the cluster size. 

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