Acid-base chemistry Arrhenius theory

The Br0nsted theory expands the definition of acids and bases to allow us to explain much more of solution chemistry. For example, the Brpnsted theory allows us to explain why a solution of ammonium chloride tests acidic and a solution of sodium acetate tests basic. Most of the substances that we consider acids in the Arrhenius theory are also acids in the Bronsted theory, and the same is true of bases. In both theories, strong acids are those that react completely with water to form ions. Weak acids ionize only slightly. We can now explain this partial ionization as an equilibrium reaction of the ions, the weak acid, and the water. A similar statement can be made about weak bases ... 

B Hess, Joule, Kelvin, and Gibbs all contributed to thermochemistry and have thermodynamic entities named after them. Volta, Faraday, and Galvani (choice D) contributed to electrochemistry, Kekule to organic chemistry, London to chemical bonding, Boyle and Charles to gas laws, Arrhenius to acid/base chemistry and thermochemstry, Pauli to quantum theory, Davy and Ramsay to element isolation, and Mendeleev to the periodic table. 

Acid-base chemistry was first satisfactorily explained in molecular terms after Ostwald and Arrhenius established the existence of ions in aqueous solution in 1880-1890 (after much controversy and professional difficulties, Arrhenius received the 1903 Nobel Prize in Chemistry for this theory). As defined at that time, Arrhenius adds form... 

Feb. 19,1859, Wijk, Sweden - Oct. 2,1927, Stockholm, Sweden). Arrhenius developed the theory of dissociation of electrolytes in solutions that was first formulated in his Ph.D. thesis in 1884 Recherches sur la conductibilit galvanique des dectrolytes (Investigations on the galvanic conductivity of electrolytes). The novelty of this theory was based on the assumption that some molecules can be split into ions in aqueous solutions. The - conductivity of the electrolyte solutions was explained by their ionic composition. In an extension of his ionic theory of electrolytes, Arrhenius proposed definitions for acids and bases as compounds that generate hydrogen ions and hydroxyl ions upon dissociation, respectively (- acid-base theories). For the theory of electrolytes Arrhenius was awarded the Nobel Prize for Chemistry in 1903 [i, ii]. He has popularized the theory of electrolyte dissociation with his textbook on electrochemistry [iv]. Arrhenius worked in the laboratories of -> Boltzmann, L.E., -> Kohlrausch, F.W.G.,- Ostwald, F.W. [v]. See also -> Arrhenius equation. 

Sumfleth [6] also states, that the idea of proton transfer may be learned by students but cannot be applied in a new context. Sumfleth and Geisler [7] show that students accept the Broensted definition, but bases are interpreted mostly based on the Arrhenius idea. Therefore, the knowledge about Broensteds concept cannot be transferred to new contexts. Sumfleth states that most students cannot really apply acid-base theories, especially at the advanced levels. This is also evident for students who have chosen chemistry as their major . 

As another example, the Brpnsted theory of acids and bases replaced the older Arrhenius theory because of its more general applicability (e.g., it applied also to non-aqueous solutions and even to gases). Attempts have been made to familiarise secondary school students with principles of quantum mechanics and thermodynamics, albeit often in a simplified and sometimes distorted form. It was expected that this would save much time because formulas and physical and chemical properties of specific compounds could then simply be derived from theoretical principles instead of having to be memorised. It was decided that many aspects of descriptive chemistry could be left out when students were provided with a small handbook covering most of the relevant facts and formulas. 

Arrhenius, Svante Ausust (1859-1927) Swedish physical chemist who, in 1884, was the first to propose that acids, bases, and salts in solution dissociated into ions. His theory of electrolytic dissociation was well before its time and was not scientifically confirmed until the theory of atomic structure was more fully developed. He also worked on reaction rates, and was the first to recognize the greenhouse effect on climate. He was awarded the Nobel Prize in chemistry in 1903. 

Arrhenius, Svante August (1859-1927) A Swedish physicist and chemist who did fundamental work on physical chemistry. He worked with van t Hoff in Amsterdam and proposed a theory of activated molecules and established a coimecdon between rate of reaction and absolute temperature. He also developed a theory for electrolytic dissociation based on van t Hoff s results and stated that any acid, base, or salt dissolved in water is partly split up into positively and negatively charged ions, and that they move in opposite directions on electrolysis. He was awarded a Nobel Prize for Chemistry in 1903. 

Theories on the nature of acids and bases are presented in most general chemistry texts [139]. The Arrhenius theory proposes that an acid is a material that releases protons (H ), and a base is a material that provides hydroxyl (OH ) ions in solution. It follows that the combination of these ions produces water ... 

Ideas about adds and bases (or alkalis) date back to ancient times. The word acid is derived from the Latin acidus (sour). Alkali (base) comes from the Arabic al-qali, referring to the ashes of certain plants from which alkaline substances can be extracted. The acid-base concept is a major theme in the history of chemistry. In this section, we emphasize the view proposed by Svante Arrhenius in 1884 but also introduce a more modern theory proposed in 1923 by Thomas Lowry and by Johannes Bronsted. 

According to the theory proposed by Svante Arrhenius, a Swedish chemist and winner of the 1903 Nobel Prize in chemistry, an acid ionizes in aqueous solution to liberate protons (H, hydrogen ions), whereas bases ionize to liberate hydroxide ions (HO ). A more general theory of acids and bases was devised independently by Johannes Brpnsted (Denmark) and Thomas M. Lowry (England) in 1923. In the Brpnsted-Lowry approach, an acid is a proton donor, and a base is a proton acceptor. 

He employed a range of adds and he correlated the affinity (reactivity) of an acid with its catalytic power. He was therefore in a good position to appreciate Arrhenius s concept of electrolytic dissociation when the latter sent him a copy of his doctoral thesis in 1884. In 1887 Ostwald moved to Leipzig as professor of physical chemistry. For the remainder of his career he championed the ionic theory of Arrhenius against much opposition. He provided additional evidence for the theory, and he developed the theory of add-base indicators. He resigned from Leipzig in 1905, and in his retirement he worked on the theory of colours, as well as espousing many humanistic, educational and cultural causes. 

Svante Arrhenius (1859-1927) was a Swedish physical chemist who was awarded the Nobel Prize in Chemistry in 1903 for his work on ionic solutions. His theory of acids and bases defined acids as substances that produce hydrogen ions in solution (as the only positive ions) and bases as substances that produce hydroxide ions (as the only negative ions). In addition he explored the relationship between the rate of a chemical reaction and temperature. The equation which bears his name was originally proposed by the Dutch chemist J.H. varit Hoff, but it was Arrhenius who provided a physical interpretation and justification for it When the temperature increases, the rate of a chemical reaction increases very rapidly. It has been found that for many reactions, the initial rate and the rate constant. 

According to the theory proposed by Svante Arrhenius, a Swedish chemist and winner of the 1903 Nobel Prize in Chemistry, an acid is a substance that ionizes to give protons when dissolved in water a base ionizes to give hydroxide ions. 

Arrhenius and Ostwald played very important roles in the early studies on add-base catalysis, one century ago. Arrhenius contributed to the definition of acids and bases, and established the dependence between the rate constants and the temperature. Additionally, he also formulated an electrolytic theory of dissociation that ultimately led to him receiving the 1903 Nobel Prize in Chemistry. Ostwald proposed useful definitions of catalysis and classifications of catalysts, but he was unable to develop a satisfactory theory of these effects. This is not surprising, in view of the very limited knowledge of the mechanisms of catalysis at his time, and of the lack of understanding of how molecular properties can influence the rates of reactions. Nevertheless, his seminal work on catalysis was rewarded by him receiving the 1909 Nobel Prize in Chemistry. 

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