Lead black

Ozone is very much more reactive than oxygen and is a powerful oxidising agent especially in acid solution (the redox potential varies with conditions but can be as high as + 2.0 V). Some examples are 1. the conversion of black lead(ll) sulphide to white lead(II) sulphate (an example of oxidation by addition of oxygen) ... 

The oxidation of black lead(II) sulphide to the white sulphate is a very sensitive test if the black sulphide is used as a stain on filter paper. 

Sulphur, as sulphide ion, is detected by precipitation as black lead sulphide with lead acetate solution and acetic acid or with sodium plumbite solution (an alkaLine solution of lead acetate). Halogens are detected as the characteristic silver halides by the addition of silver nitrate solution and dilute nitric acid the interfering influence of sulphide and cyanide ions in the latter tests are discussed under the individual elements. 

The weathering properties of polyethylene are improved by the incorporation of carbon blacks. Maximum protection is obtained using blacks with a particle size of 25 p,m and below. In practice finely divided channel or furnace blacks are used at 2-3% concentration and to be effective they must be very well dispersed into the polymer. The use of more than 3% black leads to little improvement in weathering resistance and may adversely affect other properties. 

Another approach has been adopted by the Du Pont Company with Adiprene C. This is a urethane-type polymer with unsaturated groups in the polymer. Because of the unsaturation the polymer may be vulcanised with sulphur, the standard vulcanising agent of the rubber industry. This is a clear-cut example of a product being modified to suit the processor rather than that of a processor adapting himself to meet new products. Whereas Adiprene C has poor tensile strength when unfilled, the use of carbon black leads to appreciable reinforcement (as is the case with SBR and to some extent natural rubber. 

Scbwarz-blecb, n. black plate (untinned iron plate), -blei, n. black lead (graphite), -blelerz, n. black lead spar (carboniferous cerussite). 

D-TEM gave 3D images of nano-filler dispersion in NR, which clearly indicated aggregates and agglomerates of carbon black leading to a kind of network structure in NR vulcanizates. That is, filled rubbers may have double networks, one of rubber by covalent bonding and the other of nanofiller by physical interaction. The revealed 3D network structure was in conformity with many physical properties, e.g., percolation behavior of electron conductivity. 

A commonly held belief is that lead-containing pigments react with hydrogen sulfide in polluted air to form the black precipitate lead sulfide. On exposure to hydrogen sulfide gas, all of these pigments will darken because of the formation of the black lead sulfide, PbS ... 

Pascal, P., Ed., Nouveau Traite de Chimie Minerale, Vol. 13, Masson et Cie., Paris, 1960, 528. Barton A process for making black lead monoxide by atomizing molten lead in air. BASF/CAN See CAN. 

Bischof An obsolete process for making white lead (basic lead carbonate), invented by G. Bischof around 1900. Lead monoxide was reduced by the carbon monoxide in water-gas to form black lead suboxide, oxidized in damp air to lead hydroxide, slurried in dilute acetic acid, and carbonated with carbon dioxide. Piloted in Willsden, London, and commercialized by L. Mond in the Brimsdown White Lead Company. A sample of Bischof s white lead was used by Holman Hunt in his painting Light of the World, now in St. Paul s Cathedral, London. 

Record which metals are the anode and cathode in each cell in the data table. The black lead of the probe will be attached to the metal that acts as the anode. The red lead will be attached to the cathode. 

Attach the black lead to the 2 cm piece of wire. Insert the wire into one end of the U-tube. Attach the red electrical lead to the graphite. Insert the graphite into the other end of the U-tube. 

Attach the leads to the 9-V battery or to a variable power source set to 9 V. Attach the black lead to the negative terminal, and the red lead to the positive terminal. 

The name molybdenum is derived from the Greek word for lead, molybdos, which stands for any black minerals that historically could be used for writing. This also explains why the Greek word plumbago or black lead was used for graphite. 

All organic chemicals are essentially combustible. Combustion of some chemicals, such as sulfur and sulfides of sodium, potassium, and phosphorous, result in the production of hazardous gases, in this case sulfur dioxide. Carbon black, lamp black, lead sulfocyanate, nitroaniline, nitrochlorobenze, and naphthalene are examples of combustible chemicals. 

Synonyms Plumbago black lead mineral carbon... 

In the following year Hatchett was made a Fellow of the Royal Society. In 1798 he analyzed an earthy substance, sydneia, which Josiah Wedgwood had found in New South Wales and another specimen of it provided by Sir Joseph Banks (5). This, according to Wedgwood, was composed of a fine white sand, a soft white earth, some colourless micaceous particles, and some which were black. Hatchett found it to consist of siliceous earth, alumine, oxide of iron, and black lead or graphite and concluded that the Sydneian genus, in future, must be omitted in the mineral system. ... 

The addition of sulfur results in the formation of black lead sulfide ... 

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