Midterm 2 Sp08

Midterm 2 Sp08 - CHEM173 Midterm 2 Spring 2008 Name_ UCSD...

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Name_______________________ Spring 2008 UCSD ID Number______________________ 1. Chemical Families and Cycles (60 pts: 10, 10, 10, 10, 10, 10) a) What is the name for the chemical family that includes precursors and products that can be easily converted to or from NO, NO 2 or NO 3 ? Why is it important in atmospheric chemistry? b) Name the main atmospheric reservoirs of sulfur. For each reservoir, name the chemical compound, write its chemical formula, and identify the oxidation state of sulfur. c) What is the Sulfur cycle? Describe its components, interfaces, and processes. d) What is the most important manmade type of source of NO x and SO x ? e) Which reservoir is responsible for the removal of most of the reactive nitrogen? What is the process (or processes) responsible for this removal? a) NO y is the chemical family that includes precursors and products that can be easily converted to or from NO x , such as PAN, HONO. NOy is important because compounds in the NOy family are stable enough to be transported to remote regions where they will thermally decompose into NOx and create pollution. b) The six atmospheric reservoirs of sulfur are SO 2 (sulfur dioxide, +4), SO 4 2- (sulfate, +6), H 2 S (hydrogen sulfide, -2), COS (carbonyl sulfide, -2), DMS (dimethyl sulfide, -2), and CS 2 (carbon disulfide, -2). c) The Sulfur cycle is the pathways by which and reservoirs through which compounds of nitrogen are transferred among the atmosphere, the hydrosphere (including the oceans), the biosphere (including plants), the cryosphere, and the geosphere (including soil). The primary interfaces across which sulfur is transferred are the ocean-atmosphere and the biosphere- atmosphere interfaces. The processes that control these transfers include combustion emissions (fossil fuel and biomass, anthropogenic and natural) of SO 2 , volcanic emissions of SO 4 2- and SO 2, soil emissions of H 2 S and COS, and algae production of DMS and CS 2 , and wet/dry deposition of SO 4 2- and SO 2 to the ocean and land surfaces, as well as in situ transformations. d) Fossil fuel burning.
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This note was uploaded on 10/28/2010 for the course CHEM 173 taught by Professor Dr.dancziczo during the Spring '10 term at UC Riverside.

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Midterm 2 Sp08 - CHEM173 Midterm 2 Spring 2008 Name_ UCSD...

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