Search results
Results from the WOW.Com Content Network
Recreational use of nitrous oxide. Nitrous oxide (N 2 O), commonly referred to with street names such as nangs, Nitrus, hippy crack, whippets, whippits or cannies, is an inert gas which can induce euphoria, hallucinogenic states of mind, and relaxation when inhaled. [ 1 ] Nitrous oxide has no acute biochemical or cellular toxicity and is not ...
Chlorotrifluoromethane, R-13, CFC-13, or Freon 13, is a non-flammable, non-corrosive, nontoxic chlorofluorocarbon (CFC) and also a mixed halomethane. It is a man-made substance used primarily as a refrigerant. When released into the environment, CFC-13 has a high ozone depletion potential, and long atmospheric lifetime. [2]
The most common engineering classification system for soils in North America is the Unified Soil Classification System (USCS). The USCS has three major classification groups: (1) coarse-grained soils (e.g. sands and gravels); (2) fine-grained soils (e.g. silts and clays); and (3) highly organic soils (referred to as "peat").
The adduct with diethyl ether, boron trifluoride diethyl etherate, or just boron trifluoride etherate, (BF3·O(CH2CH3)2) is a conveniently handled liquidand consequently is widely encountered as a laboratory source of BF3.[15] Another common adduct is the adduct with dimethyl sulfide(BF3·S(CH3)2), which can be handled as a neat liquid.
Bromine trifluoride is an interhalogen compound with the formula BrF 3. At room temperature, it is a straw-coloured liquid with a pungent odor [5] which decomposes violently on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent.
Dichlorodifluoromethane (R-12) is a colorless gas usually sold under the brand name Freon-12, and a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. In compliance with the Montreal Protocol, its manufacture was banned in developed countries (non-article 5 countries) in 1996, and in developing countries ...
The 8-4-4 System educational program is a system of education in Kenya with eight years of primary education, four years of secondary education and four years of university education. [ 1 ] The system was introduced in 1985 to replace the 7-4-2-3 curriculum, which consisted of seven years of primary school (classes 1–7), four years of lower ...
Nuffield Science Project. The Nuffield Science Teaching Project was a programme to develop a better approach to teaching science in British [n 1] secondary schools, under the auspices of the Nuffield Foundation. Although not intended as a curriculum, it gave rise to alternative national examinations, and its use of discovery learning was ...