Copper in nitric acid

Oxadiazinium hexachlorantimonates are reported to stimulate the dissolution of aluminum in acetonitrile <91MI 618-02), but to inhibit that of copper in nitric acid <89Ml 521-02). 

The starting material, cupric nitrate, may be obtained by dissolving electrolytic copper in nitric acid and evaporating the solution to dryness on a steam bath ... 

Zarrouk A, Dafali A, Hammouti B, Zarrok H, Boukhris S, Zertoubi M (2010) Synthesis, characterization and comparative study of functionalized quinoxaline derivatives towards corrosion of copper in nitric acid medium. Int J Electrochem Sci 5(l) 46-55... 

Addition of water gives the hydrated nitrate Cu(N03)2.3H2O, the product obtained when copper (or the +2 oxide or carbonate) is dissolved in nitric acid. Attempts to dehydrate the hydrated nitrate, for example by gently heating in vacuo, yield a basic nitrate, not the anhydrous salt. 

The dissolution of copper and of brasses in acid solutions has been studied by several authors". Various substances have inhibiting effects on the rate of attack of copper or brasses in nitric acid" and in hydrochloric acid". ... 

Austenitic stainless steels-determination of resistance to intergranular corrosion. Part 1 Corrosion test in nitric acid medium by measurement of loss of mass (Huey test) Austenitic stainless steels-determination of resistance to intergranular corrosion. Part 2 Corrosion test in a sulphuric acid/copper sulphate medium in the presence of copper turnings (Moneypenny Strauss test)... 

Chakraborti et al. [665] determined cadmium, cobalt, copper, iron, nickel, and lead in seawater by chelation with diethyldithiocarbamate from a 500 ml sample, extraction into carbon tetrachloride, evaporation to dryness, and redissolution in nitric acid prior to determination by electrothermal atomic absorption spectrometry in amounts ranging from 10 pg (cadmium) to 250 pg (nickel). 

Berndt et al. [740] have shown that traces of bismuth, cadmium, copper, cobalt, indium, nickel, lead, thallium, and zinc could be separated from samples of seawater, mineral water, and drinking water by complexation with the ammonium salt of pyrrolidine- 1-dithiocarboxylic acid, followed by filtration through a filter covered with a layer of active carbon. Sample volumes could range from 100 ml to 10 litres. The elements were dissolved in nitric acid and then determined by atomic absorption or inductively coupled plasma optical emission spectrometry. 

In Section 20.2, a redox reaction involving copper and nitric acid is discussed. This reaction is balanced by a method called the oxidation-number method. In this lab, you will carry out this reaction, along with another redox reaction that involves a common household substance. You will practice balancing various redox reactions using both the oxidation-number method (from Section 20.2) and the half-reaction method (from Section 20.3). 

The reaction of copper with nitric acid should be done in a ventilation hood. Do not breathe the fumes from this reaction. 

Applying Concepts The reaction between copper and nitric acid is discussed in Section 20.2. Write the half-reaction for the substance that is oxidized. 

As an example, use that method to balance the preceding reaction involving copper and nitric acid. Begin by writing oxidation numbers for all the elements in each substance, as follows ... 

Elemental composition Cu 57.47%, C 5.43%, H 0.91%, 0 36.18%. Both malachite and azurite may be identified by x-ray analysis and analyzed qualitatively using physical properties such as refractive index and density. For quantitative analysis, the compound may he digested in nitric acid and analyzed for copper by various instrumental methods (see Copper.)... 

Elemental composition Cu 64.18%, Cl 35.82%. Copper(I) chloride is dissolved in nitric acid, diluted appropriately and analyzed for copper by AA or ICP techniques or determined nondestructively by X-ray techniques (see Copper). For chloride analysis, a small amount of powdered material is dissolved in water and the aqueous solution titrated against a standard solution of silver nitrate using potassium chromate indicator. Alternatively, chloride ion in aqueous solution may be analyzed by ion chromatography or chloride ion-selective electrode. Although the compound is only sparingly soluble in water, detection limits in these analyses are in low ppm levels, and, therefore, dissolving 100 mg in a liter of water should be adequate to carry out aU analyses. 

Elemental composition Cu 70.95%, C 13.41%, N 15.64%. Copper(I) cyanide is decomposed in nitric acid and the acid extract diluted appropriately and analyzed for copper hy various instrumental methods (see Copper). 

Elemental composition Cu 33.36%, I 66.64%. Either compound or mineral copper(I) iodide is identified by x-ray diffraction or fluorescence method. Copper may be analyzed in nitric acid extract of copper(I) iodide by various instrumental techniques (see Copper). 

Although no one had ever succeeded in extracting copper from Kupfernickel, J. H. Linck (or Link) stated in 1726 that, since it gives green solutions when dissolved in nitric acid, it must be a cobalt ore... 

If 100 parts of this carbonate, dissolved in nitric acid and separated by the alkaline carbonates, gives us 100 parts of artificial carbonate, and if the base of these two combinations is the black oxide, we must recognize that invisible hand which holds the balance for us in the formulation of compounds and fashions properties according to its will. We must conclude that nature operates not otherwise in the depths of the world than at its surface or in the hands of man. These ever-invariable proportions, these constant attributes, which characterize true compounds of art or of nature, in a word, this pondus naturae so well seen by Stahl all this, I say, is no more at the power of the chemist than the law of election which presides at all combinations. From these considerations is it not right to believe that the native carbonate of copper... 

As an illustration of the use of electrode potentials, consider the classical method of analysis of copper in brass, which involves dissolving the weighed sample in nitric acid to obtain Cu2+(aq), adjusting the pH to a weakly acidic level, allowing the Cu2+ to react completely with excess potassium iodide to form iodine and the poorly soluble Cul, and then titrating the iodine with sodium thiosulfate solution that has been standardized against pure copper by the same procedure ... 

Pass a stream of hydrogen sulphide through the nitric acid in the fourth test tube. Write the equation of the reaction. Introduce a small amount of copper sulphide into the fifth tube with nitric acid. Explain why it dissolves in nitric acid. Write the equation of the reaction. 

Puke Silver.—The silver of commerce is never perfectly pure, being always mixed with a certain proportion of copper mid traces of other metals.. A small quantity may he obtained pure by dissolving a piece of money or of plate in nitric acid, and adding a solution of chloride of sodium a double decomposition occurs the silver Is thrown down in tlio form of an insoluble chloride, while the copper and any other metals that may he present remain Id solution. One huudred parts of this chloride are, when separated and dried, mixed with seventy parts of chalk and four or five of carbon, and this mixture is introduced into a crucible aud raised to a white heat. Carbonic oxido is disengaged, and ohioride of calcium and metallic silver remain in the crucible. 

Nitrate of Silver—Ag 0 NOs—constitutes the most important salt of this metal. It is obtained by dissolving silver in nitric acid diluted with three parte of water nitric oxide is disengaged, and if tho silver contain copper, the solution will have a bluish tinge if gold, that metal will remain undissolved In the form of a black powder. The solution of nitrate of silver should be perfectly clear and oolorless. It is caustic, and tinges... 

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