Chlorofluorocarbons formula

En español: Dedicated at the University of California, Irvine on April 18, 2017. The language is dry and academic, as is appropriate for the abstract of a scientific paper in the prestigious journal Nature. The research described in the short paper, however, fell like a scientific bombshell, one whose repercussions would be felt around the world. It set off fierce debates, led to a global environmental treaty restricting the use of a broad class of chemicals, and changed the way humans viewed their impact on Earth’s environment. It also led to F. Sherwood Rowland (1927-2012) and Mario J. Molina (*1943) sharing the 1995 Nobel Prize in Chemistry with Paul J. Crutzen of the Max Plank Institute for Chemistry, Mainz, another pioneer in stratospheric ozone research. Rowland, a professor of chemistry at the University of California, Irvine, and Molina, a postdoctoral fellow in Rowland’s laboratory, had shown that chlorofluorocarbons—CFCs—could destroy ozone, a molecule made up of three oxygen atoms, O 3, in Earth’s stratosphere. That stratospheric ozone absorbs ultraviolet radiation that otherwise would reach the surface of Earth. At the time, CFCs were in wide use in refrigeration, air conditioning and aerosol spray cans. The compounds are inert and essentially nontoxic, characteristics that made them well-suited for these applications. These same characteristics, however, also made them a danger to life on Earth. Landmark Lesson Plan: Chlorofluorocarbons and Ozone Depletion NAS...

chlorofluorocarbon (CFC), any of several hydrochlorofluorocarbons, or HCFCs. CFCs are also called trichlorofluoromethane (CFC-11) and Their commercial and industrial value notwithstanding, CFCs were eventually discovered to pose a serious environmental threat. Studies, especially those of American chemists The chlorine atoms then react with ozone, initiating a process whereby a single chlorine atom can cause the

Chlorofluorocarbon Chlorofluorocarbons (CFCs) are compounds composed of carbon, fluorine, chlorine, and sometimes hydrogen. From: Solid and Hazardous Waste Management, 2017 Related terms: • Energy Engineering • Aqueous Solution • Global Warming • Global Warming Potential • Greenhouse Gas • Ozone Depletion Potential • Ozone Layer • Ultimate Tensile Strength Arid Catchments Neil L. Ingraham, ... Balthazar Th. Verhagen, in Isotope Tracers in Catchment Hydrology, 1998 13.4.5Chlorofluorocarbons Chlorofluorocarbons (CFCs) have recently been applied in catchment hydrology studies as a tool for dating very young groundwaters. CFCs are stable, anthropogenic organic compounds that have been produced since the 1930's for aerosol propellants and refrigerants. Once released to the atmosphere, chlorofluorocarbons CFCl 3, CF 2Cl 2 and C 2F 3Cl 3 have relatively long residence times (44, 180, and 85 yrs, respectively), where they undergo equilibration with surface waters as a function of temperature. As a result, groundwater containing CFCs must have a component of modern recharge water. Therefore, by measuring CFC concentrations and estimating the recharge temperature in a groundwater sample, a CFC-model age can be determined. CFCs have been used as tracers and as age-dating tools by Thompson et al. (1974), Randall and Schultz (1976), Schultz et al. (1976), Thompson and Hayes (1979), Busenberg and Plummer (1992), Dunkle et al. (1993), Ekwurzel et al. (1994), Reilly et al. (1994), and Hin...

Swedish Pollutant Release and Transfer Register Chlorofluorocarbons (CFCs) CFC, Klorfluorkarboner, fullständigt halogenerade Name PRTR Chlorofluorocarbons (CFCs) CAS no - Molecular formula - Chlorofluorocarbons (CFCs) is a group of halogenated hydrocarbons consisting of a short carbon chain. CFCs are also known under the trade name Freon 1. These substances evaporate easily and are very stable. Uses The use CFCs has been prohibited since the mid 1990’s 2. Before that, CFCs were used in spray cans as a solvent and as a propellant. CFCs have also been used as a cooling agent in refrigeration and air conditioning systems and in refrigerators 3. During the 1960’s to the 1990’s CFCs were used as a blowing agent during production of insulation materials for use in district heating pipes, water heaters, ground slabs, walls and so forth. The two most common insulation materials containing CFCs are PUR (polyurethane) and XPS (extruded polystyrene) 4. Sources and transportation pathways Nowadays insulation material is the largest source of CFC emissions 5. Emissions of CFCs from insulation material occur both during incorrect disposal of CFC containing construction material during demolition and by passive leakage of CFCs from insulation material. In addition, CFC emissions also occur from products where CFCs have been used as cooling agents. Effects on environment and health The gaseous chlorofluorocarbons have a strong ozone depleting effect. A thinner ozone layer contributes to i...

Ozone has always had natural enemies in the atmosphere. One of them is nitrogen (NO), but chlorine (Cl) has been added to the list over thepast century. In fact, its concentration has increased due to human-related activities, breaking the delicate balance of the stratosphere. Let’s see in detail how CFCs, combined to ozone molecules, cause the ozone depletion. The introduction of ozone into the stratosphere occurs through CFCs (Chlorofluorocarbons). CFCs, composed by chlorine, fluorine, and carbon, have a long lifecycle, which favours their accumulation. CFCs do not easily react with other substances. In fact, they break up only through sunlight, which divides their molecules, causing the release of chlorine (Cl). Once the chlorine is released, it is able to react with ozone (O3), to form chlorine monoxide (ClO) and oxygen (O2). Cl + O3 = ClO + O2 When the molecule of chlorine monoxide (ClO) meets another molecule of oxygen (O) it breaks up, releasing chlorine (Cl), which can “destroy” another molecule of ozone (O3), creating the catalytic cycle of chlorine. ClO + O = Cl + O2 The industrial production of CFCs started in the 1920’s, causing an average reduction of the ozone layer of 3 per cent. Fortunately, chlorine has “natural enemies” as well, such as methane (CH4). Thanks to them, the natural ozone layer could recover over 50 years, as long as CFCs are no longer used on a global level. The ozone depletion is also referred to as the “ozone hole”, due to the fact that it...

Before Thomas Midgley Jr. and his associates invented Freon in 1928, the most common refrigerants were dangerous chemicals such as sulfur dioxide, methyl chloride and ammonia. Freon is a combination of several chlorofluorocarbons, or CFCs, which are so chemically inert that engineers believed they had found a miracle compound. CFCs are tasteless, odorless, nonflammable and noncorrosive, but in 1974, two scientists warned that they are far from harmless, and their warnings were confirmed in 1985. Oxygen is the second most abundant gas in Earth's atmosphere, and it exists primarily as molecules made of two oxygen atoms. Oxygen can combine into molecules with three atoms, however, which are called ozone. Ozone near the ground is a pollutant, but in the upper stratosphere, it forms a protective layer around the planet that absorbs ultraviolet sunlight, thereby protecting all life from the harmful effects of that radiation. The thickness of this layer is measured in Dobson units (DU); one DU is one-hundredth of a millimeter at standard temperature and pressure. The ozone layer is about 300 to 500 DU thick on average, which is about the thickness of two stacked pennies. The Effect of CFCs Scientists first began to realize the potential for chlorine to interact destructively with ozone in the early 1970s, and Sherwood Rowland and Mario Molina warned of the danger that CFCs posed to the ozone layer in 1974. This danger is a direct consequence of the fact that CFCs -- which contain...