Gases Precautions

Because ammonium bicarbonate can produce so much gas, precautions must be taken to ensure that it is uniformly distributed throughout the product lest large voids should appear in the finished item. The practical solution to this problem is to make a solution of ammonium bicarbonate in warm water and add that to the mixer rather than adding the solid with the other ingredients. 

Sulphur mustard may be used as a chemical warfare agent in a number of ways. It may be delivered by artillery shell, rocket, bomb or aircraft spray. The agent is persistent and under cold conditions long-term contamination of ground may occur. Adequately protected troops would be expected to withstand well an attack with mustard gas. Precautions should be taken to ensure that protected troops do not carry mustard, for example on boots, into designated clean areas . 

German High School students are given a lesson in gas precautions. 

Some special points arise from the nature of the radioactive parent substance radium and the daughter radon, which is an alpha-emitting inert gas. Precautions must be taken when sampling to prevent the gas escaping from the water prior to measurement and, on the other hand, to prevent its... 

In 1917 there had been rumours that the Germans intended to use gas against the British civilian population, and in the spring of 1918 the War Cabinet had considered the advisability of taking anti-gas precautions on a wide scale.For the next 25 years the threat of aerial gas bombardment was to be a constant preoccupation. In the Cabinet Lord Fisher had voiced fears about the effects of gas attacks on cities. In February 1927 Professor Noel Baker broadcast on the radio a description of a gas attack from the air and asserted that all the experts are agreed that it would be impossible to devise means to protect the civilian population from this form of attack . ... 

In April 1939 the government told the House of Commons that the level of gas protection rendered the risk of gas attack less likely . There was some criticism that too much effort was being put into anti-gas precautions but the experts were not prepared to advise the Home Office that there had been a substantial decrease in the risk. ... 

This tube is connected %vith rubber tubing of about 6 mm. bore to the carbon dioxide Kipp, via a wash-bottle containing sodium carbonate solution (to remove any dilute hydrochloric acid spray). It is very important, when the apparatus is in use, that there should be no constriction or bend in the rubber tube between the tap C and the wash-bottle. If these precautions are taken, a slow, e en, and easily controlled flow of gas can be obtained. 

The most dangerous solvent in the laboratory is carbon disulphide, the flash-point of which is so low that its vapour is ignited, e.g., by a gas-ring 3 4 minutes after the gas has been turned out. CarlK>n disulphide should therefore never be used in the laboratory unless an adequate substitute as a solvent cannot be found. Probably the next most dangerous liquid for general manipulation is ether, which, however, has frequently to be employed. If the precautions described on pp. 79, 163, are always followed, the manipulation of ether should however quite safe. 

Hydrogen chloride. Method 1 from concentrated sulphuric acid and fused ammonium chloride). The most convenient procedure is to allow concentrated sulphuric acid to react with lumps of fused ammonium chloride in a Kipp s apparatus. The gas may be dried by passage through a wash bottle containing concentrated sulphuric acid the latter should be followed by an empty wash bottle or flask as a precaution against sucking back of the contents of the reaction vessel. 

The effluent from a GC column is already in the gas phase and needs only to be mixed with argon makeup gas before passage into the flame. Precautions need to be taken to divert temporarily the GC flow when the first solvent peak emerges because it contains far too much material for the plasma to withstand. 

Specialty Gases. The purity of specialty gases depends on the systems and procedures adopted by the distributors for bulk gas supply and cylinder preparation, filling, and deHvery. The distributors need to foUow strict cylinder selection, preparation, and filling procedures to ensure the quaHty of the products. Most of the precautions taken into consideration in the bulk gases deHvery system are also appHed for specialty gases to eliminate recontamination. 

Storage, Shipping, and Handling. Phosphoms pentachloride is in the EPA extreme ha2ardous substance Hst. It is treated as a dammable sohd, and containers in which it is stored or shipped must be affixed with a yellow acid label DOT UN No. 1806. In general, the pentachloride should be handled with the same precautions that are used with the trichloride. Protective clothing should be worn by workers handling the pentachloride and gas masks should be used when personnel are exposed to the vapors. 

Cross-country gas pipelines generally must odorize the normally odorless, colorless, and tasteless gas ia urban and suburban areas, as is required of gas distribution companies. Organosulfur compounds, such as mercaptans, are usually used for this purpose, and code requires that the odor must be strong enough for someone with a normal sense of smell to detect a gas leak iato air at one-fifth the lower explosive limit of gas—air mixtures. The latter is about 5%, so the odorant concentration should be about 1%, but most companies odorize more heavily than this as a safety precaution. 

By far the largest proportion of gas sampling operations in industry is carried out for environmental reasons and the sampling methods employed have been thoroughly researched and are well documented (5—12). The preparation, precautions and equipment requirements involved in the sampling of air pollution sources are appHcable to most other gaseous environments (see Airpollution control methods). 

The toxicity of vanadium alloys may depend on other components in the alloy. For example, the V Ga alloy requires precautions related to both vanadium and gaUium, and gallium is highly toxic. Similarly, alloys with chromium may require precautions associated with that metal. 

Precaution should be taken to avoid accidental generation of arsine gas the maximum permitted exposure is 0.05 ppm in air per 8-h period five days per week (34). Disposal of arsenical products should be in compliance with Eederal and local government environmental regulations. 

Dichlorine monoxide is the anhydride of hypochlorous acid the two nonpolar compounds are readily interconvertible in the gas or aqueous phases via the equilibrium CI2 O + H2 0 2H0Cl. Like other chlorine oxides, CI2O has an endothermic heat of formation and is thus thermodynamically unstable with respect to decomposition into chlorine and oxygen. Dichlorine monoxide typifies the chlorine oxides as a highly reactive and explosive compound with strong oxidhing properties. Nevertheless, it can be handled safely with proper precautions. 

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