Decomposition of potassium

Pure oxygen is conveniently prepared by the thermal decomposition of potassium manganate(VII) ... 

The decomposition of potassium chlorate(V) is catalysed by manganese(IV) oxide, Mn02, and oxygen is evolved on heating the mixture below the melting point of the chlorate(V). 

It catalyses the decomposition of potassium chlorate(V). Mixed with zinc oxide, it is used as a catalyst in the manufacture of methanol. It is used as a pigment, being very resistant to weathering. 

Manganese(IV) oxide is a dark-brown solid, insoluble in water and dilute acids. Its catalytic decomposition of potassium chlor-ate(V) and hydrogen peroxide has already been mentioned. It dissolves slowly in alkalis to form manganates(lW), but the constitution of these is uncertain. It dissolves in ice-cold concentrated hydrochloric acid forming the complex octahedral hexachloromangan-ate(IV) ion ... 

Decomposition of potassium ferratefVI) at 1000 K gives a ferrate V), K3Fe04, and several types of ferrate(IV), for example FeOj", Fe04 are known these ferrates(IV) have no solution chemistry and are probably best regarded as mixed oxides, since the FeOl" ion has no identifiable structure. 

It states that the rate is proportional to the fraction x that has decomposed (which is dominant early in the reaction) and to the fraction not decomposed (which is dominant in latter stages of reaction). The decomposition of potassium permanganate and some other solids is in accordance with this equation. The shape of the plot of x against t is sigmoid in many cases, with slow reactions at the oeginning and end, but no theory has been proposed that explains everything. 

Oxygen occurs free in air in which it forms 21% by volume. It is also found combined with hydrogen in water and constitutes 86% of the oceans, and with other elements such as minerals constituting ca 50% of the earth s crust. In the laboratory it is usually prepared by the thermal decomposition of potassium chlorate in the presence of manganese dioxide catalyst ... 

In general, the decomposition of potassium metaniobate, forming niobium oxide, can be represented as follows ... 

The most effective of the proposed solutions seem to be solutions of ammonium carbonate, (NH4)2C03. Such solutions were also recommended by Mulyarchuk and Panchenko [500] for the decomposition of potassium fluorosilicate, K2SiF6. 

Szava, Factors which Influence Thermal Decomposition of Potassium Picrate , 8th Symp Combstn (1962), 863—72... 

This is known as the Prout—Tompkins equation and has found application to many systems, in addition to the thermal decomposition of potassium permanganate [465] with which it is often associated. The kinetic behaviour of silver permanganate was somewhat different and in a variation of... 

Reference has already been made to the dehydration of alums (Sect. 1.2 and Table 10), decomposition of ammonium metal phosphates (Sect. 4.1.5) and the use of KMn04—KCIO4 solid solutions in mechanistic studies of the decomposition of potassium permanganate (Sect. 3.6). 

Write the balanced chemical equation for (a) the thermal decomposition of potassium chlorate without a catalyst (b) the reaction of bromine with water (c) the reaction between sodium chloride and concentrated sulfuric acid, (d) Identify each reaction as a Bronsted acid—base, Lewis acid—base, or redox reaction. 

Theoretically, all chemical reactions are reversible. There are, however, many reactions in which the extent of the reverse reaction (i.e., combination of the products to produce the reactants) is very small as to be considered negligible. Such reactions which are ordinarily found to proceed to completion in one direction are said to be irreversible reactions. The decomposition of potassium chlorate... 

The procedure described for the preparation of l-(m-nitro-phenyl)-3,3-dimethyltriazene is the method of Elks and Hey,2 and the preparation of m-nitrobiphenyl is also a modification of their procedure. The other principal methods for the preparation of m-nitrobiphenyl are the decomposition of N-nitroso-w-nitroacetanilide in benzene 3 and the decomposition of alkaline m-nitrobenzenediazohydroxide in benzene.4 Other methods that have been reported include the decomposition of potassium ire-nitrobenzenediazotate in benzene with acetyl chloride,6 the decomposition of m-nitrobenzoyl peroxide in boiling benzene,6 the decomposition of benzenediazonium borofluoride in nitrobenzene 7 at 70°, and the reduction of 4-(3 -nitrophenyl)-benzenediazonium acid sulfate in boiling ethanol.8... 

Action of chlorine trifluoride causes incandescence [1]. Manganese dioxide catalytically decomposes powerful oxidising agents, often violently. Dropped into cone, hydrogen peroxide, the powdered oxide may cause explosion [2], Either the massive or the powdered oxide explosively decomposes 92% peroxomonosulfuric acid [3], and mixtures with chlorates ( oxygen mixture , heated to generate the gas) may react with explosive violence [4], Cuban pyrolusite can be used in place of potassium dichromate to promote thermal decomposition of potassium chlorate in match-head formulations [5],... 

The halic acids may not be industrially important, but their salts certainly are. Sodium chlorate is produced in enormous quantities and used in processes in which its oxidizing strength makes it a versatile bleach. One such use is in making paper, and potassium chlorate is used as the oxidizing agent in matches. The decomposition of potassium chlorate was discussed in Chapter 13 in connection with the laboratory preparation of oxygen. 

Wiegand GH, Tremelling M. 1972. The kinetics and mechanism of the decomposition of potassium cyanide in aqueous alkaline medium. Hydrolysis of the simplest nitrile. J Org Chem 37(6) 914-916. 

I) Decomposition of potassium chlorate in the presence of solid Mn02 Mn02... 

The composition and constitution of perchloric acid.—The composition of perchloric acid was established by F. von Stadion,80 and verified by J. L. Gay Lussac by the decomposition of potassium chlorate. 10 03 grams of perchloric acid were dissolved in water, and treated with a small excess of potassium carbonate. The soln. was evaporated to dryness with a slight excess of acetic acid, and washed with absolute alcohol to remove the potassium acetate. The residual potassium perchlorate was dried and weighed. The potassium perchlorate was ignited to drive off the oxygen. The results were ... 

G. Tschermak also obtained crystals of potassium hydrosulphate, KHSO4, by the slow decomposition of potassium ethyl sulphate, or by treating alcoholic potash with sulphuric add. J. Kendall and M. L. Landon obtained evidence of the hydrosulphate from the f.p. curve of the Components its m.p. is given as 218 6°, and there are three modifications with transition points at 182° and 202°. 

Tompkins et al. [22, 85] studied the photochemical decomposition of potassium and barium azide. Originally they found that the rate of photolysis was proportional to the square of the intensity of the radiation. 

Gordon and Campbell [86], for instance, examined the exothermic decomposition of potassium perchlorate mixtures with carbon within the temperature range 300-360°C, while Grodzinski [87] studied the thermal decomposition of mixtures of various combustibles with potassium perchlorate. 

The reagent can be prepared in situ, by the copper-catalyzed oxidation of hydrazine. Hydrogen peroxide or oxygen are often the oxidants. The acid-catalyzed decomposition of potassium azodicarboylate provides a useful source of diimide ... 

Reaction rates are affected not only by reactant concentrations and temperature but also by the presence of catalysts. A catalyst is a substance that increases the rate of a reaction without being consumed in the reaction. An example is manganese dioxide, a black powder that speeds up the thermal decomposition of potassium chlorate ... 

E.S. Freeman, The Kinetics of the Thermal Decomposition of Potassium Nitrate and of the... 

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