Ammonium sulphate, crystal

Ammonium Sulphate. Put several ammonium sulphate crystals on the lid of a crucible and roast them. Write the equation of the reaction of thermal dissociation of ammonium sulphate. 

Preparation of Copper(II) and Ammonium Sulphate. Dissolve 1 g of copper(II) sulphate pentahydrate in 2 ml of water with heating and prepare a solution containing an equimolecular amount of ammonium sulphate saturated at 60 °C. Pour together the two hot solutions, mix them, and let them stand for crystallization. Examine the crystals under a microscope and compare their shape with that of copper(II) sulphate pentahydrate and ammonium sulphate crystals. What is the composition of the product Into what ions does this salt dissociate in an aqueous solution Check whether copper(II) hydroxide will precipitate from an aqueous solution of the obtained salt when a sodium hydroxide solution is added to it ... 

Ammonium sulphate crystallizes from solution as the anhydrous salt, (NH4) 2SO4 j copper sulphate as the hydrate, CuS04-5H20 but when equivalent amounts of the two salts are in solution together the double salt, (NH SCh-CuSCh-fiH, separates first because it is less soluble than either of the single salts. 

More often the ammonium sulphate crystals are removed from the saturator by means of a steam discharger (working on the principle of the air lift), which drives it in the form of a coarse mud, together with a considerable amount of mother liquor, on to the drainer, and thence it is passed into the centrifugal machines, the mother liquors invariably running back into the saturator. In this type of plant a closed saturator is used, as described below —... 

Figure 6.40. Habit changes in ammonium sulphate crystals caused by traces of impurity.

Mullin, J.W. and Osman, M.M. (1973) Nucleation and precipitation of nickel ammonium sulphate crystals from aqueous solution. Kristall und Technik, 8, 471-481. 

Mullin, J.W., Chakraborty, M. and Mehta, K. (1970) Nucleation and growth of ammonium sulphate crystals. Journal of Applied Chemistry, 20, 367-371. 

Five grams of precursor are refluxed for 1 h in about 200 cm distilled water, cooled, filtered and made up to volume in a 250 cm standard flask. An indicator is prepared by dissolving 500 g of ferric ammonium sulphate crystals in 700 cm distilled water. Now take 200 cm of this concentrated solution, add 400 cm concentrated HNO3 and making up to 1 litre with distilled water. Take a 10 cm aliquot and add 1 cm ferric alum indicator, measure the optical density in a spectrophotometer at 510 pm against a blank of 10 cm distilled water and 1 cm ferric alum indicator. The ppm level of NaSCN can be determined from a calibration graph. 

Example How would the addition of Al3+ affect the habit of ammonium sulphate crystals The lattice dimensions of ammonium sulphate are a - 0.595 nm. b -1.056 nm. c - 0.773 nm. and that of aluminium ammonium sulphate is a = 1.22 nm. Each basal surface of ammonium sulphate cells contains two molecules. Their mean distances are as follows ... 

Nienow and Conti (1978) developed a model of particle abrasion at high solids concentration based on Rittinger s law of comminution. When tested experimentally using copper sulphate and nickel ammonium sulphate crystals in two non-solvent liquids, measured abrasion rates were consistent with a second-order dependence of concentration as predicted (Figure 5.12). 

Procedure (copper in crystallised copper sulphate). Weigh out accurately about 3.1 g of copper sulphate crystals, dissolve in water, and make up to 250 mL in a graduated flask. Shake well. Pipette 50 mL of this solution into a small beaker, add an equal volume of ca AM hydrochloric acid. Pass this solution through a silver reductor at the rate of 25 mL min i, and collect the filtrate in a 500 mL conical flask charged with 20 mL 0.5M iron(III) ammonium sulphate solution (prepared by dissolving the appropriate quantity of the analytical grade iron(III) salt in 0.5M sulphuric acid). Wash the reductor column with six 25 mL portions of 2M hydrochloric acid. Add 1 drop of ferroin indicator or 0.5 mL N-phenylanthranilic acid, and titrate with 0.1 M cerium(IV) sulphate solution. The end point is sharp, and the colour imparted by the Cu2+ ions does not interfere with the detection of the equivalence point. 

Urea. 50 g of potassium cyanide is heated in an iron cmcible under a large flame until it begins to fuse. 140 g of red lead is added in small portions, while the mixture is stirred with a rod. When the addition is complete and the frothing has stopped, the fused mass is poured onto an iron tray. When cold, the mass is separated from metallic lead, ground up, and digested with 200 cc of cold water for 1 hour. The filtrate from this mixture is treated with 25 g of ammonium sulphate and evaporated to dryness on a water bath. The residue is powdered well, transferred to a flask and is boiled with 3 installments of ethanol under reflux, to dissolve the urea from the potassium sulphate. Each of the 3 ethanol extracts is filtered, then combined, and evaporated to a small bulk, until crystals of urea separate on cooling and standing. Mp 132°. 

Table 15.3 Crystallization conditions for DNA-protein complexes using ammonium sulphate as a precipitant... 

It separates in small violet rhombic crystals which resemble chloro-pentammino-cobaltic chloride in appearance. It is soluble in cold water to a certain extent, and only two-thirds of the chlorine is precipitated from solution by silver nitrate at ordinary temperature. In aqueous solution the salt is gradually transformed into the diaquo-salt, [Co(NH3)4(HaO)2]Cl3 dilute nitric acid, if rubbed with the substance, gives reddish-violet crystals of the nitrate, [Co(XH3)4(HaO)Cl](NOs)2 and a cold concentrated solution of ammonium sulphate yields the sulphate, [Co(NH3)4(H20)C1]S04. The corresponding bromide, [Co(NH3)4(H2Q)Cl]Br2, is obtained by filtering a cold saturated solution of the chloride into concentrated hydrobromie acid at 0° C. The precipitate formed is washed with hydrobromie acid and then with alcohol. The bromide is almost insoluble in hydrobromie acid, but more easily soluble in water than the chloride.2... 

Ammonium chloride is also formed by the action of hydrochloric acid on a soln. of ammonia or ammonium carbonate J. G. Qentele 5 made it by the double decomposition of ammonium bicarbonate and sodium, magnesium, calcium, and other chlorides H. J. E. Hennebutte and E. Mesnard, and A. Dubose and M. Heuzey, made it by the action of ammonium bicarbonate or sulphate on the double chloride of iron and calcium and it is made by the action of soln. of ammonium sulphate and sodium chloride when the soln. is cone, the crystals of sodium sulphate separate out and they are removed by suitable shovels the cone. soln. of ammonium chloride which remains is purified by crystallization. Ammonium chloride can also be obtained by sublimation from a dry intimate mixture of the same two salts. A. French made it by the joint action of air and steam on a mixture of salt, pyrites, and carbon or organic matter 2NaCl+4H20-j-S02+C-j-N2=2NH4Cl-i-Na2S04-i-C02. 

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