Particulate perspective

This coherent picture involves three levels of understanding or perspectives on the nature of chemistry macroscopic, microscopic, and symbolic. By the end of this course, you should be able to switch among these perspectives to look at problems involving chemistry in several ways. The things we can see about substances and their reactions provide the macroscopic perspective. We need to interpret these events considering the microscopic (or particulate ) perspective, where we focus on the smallest components of the system. Finally, we need to be able to communicate these concepts efficiendy, so chemists have devised a symbolic perspective that allows us to do that. We can look at these three aspects of chemistry first, to provide a reference for framing our studies at the outset. 

The particulate perspective provides a more detailed look at the distinction between chemical and physical changes. Because atoms and molecules are far too small to observe directly or to photograph, typically we will use simplified, schematic drawings to depict them in this book. Often, atoms and molecules will be drawn as circles to depict them and consider their changes. 

When we try to visualize a chemical concept using drawings, we will start from the conventions that were introduced for the particulate perspective of chemistry in Section 1.2. In this type of problem, we could be asked, for example, to draw a diagram that depicts what happens to the molecules when steam condenses into liquid water. Example Problem 1.7 illustrates this type of thinking. 

Obviously, the solutions to conceptual questions like this are less exact than numerical answers. So your drawing might look somewhat different, yet still be correct. Neither the gas nor the solid needs to look exactly like the picmre we have drawn, but the drawing itself should impart the essential concepts we need to understand when thinking about the particulate perspective of this process. 

Some farmers use ammonia, NH3, as a fertilizer. This ammonia is stored in liquid form. Use the particulate perspective to show the transition from liquid ammonia to gaseous ammonia. 

Alicroscopic perspective (1.2) Viewpoint of chemistry focusing on samples of matter at the atomic and molecular level, where samples cannot be seen, measured, or handled easily. Note that this scale is smaller than the resolution of a traditional microscope. Also called the particulate perspective. 

Evans, P.H., Klinowski, J. and Yano, E. (1991). Cephaloconi-osis a free radical perspective on the proposed particulate-induced etiopathogenesis of Alzheimer s dementia and related disorders. Med. Hypoth. 34, 209-219. 

The sedimentary and metamorphic rocks uplifted onto land have become part of continents or oceanic islands. These rocks are now subject to chemical weathering. The dissolved and particulate weathering products are transported back to the ocean by river runoff. Once in the ocean, the weathering products are available for removal back into a marine sedimentary reservoir. At present, most mass flows on this planet involve transport of the secondary (recycled) materials rather than the chemical reworking of the primary (juvenile) minerals and gases. The natirre of these transport and sediment formation processes has been covered in Chapters 14 through 19 from the perspective of the secondary minerals formed. We now reconsider these processes from the perspective of impacts on elemental segregation between the reservoirs of the crustal-ocean-atmosphere factory and the mantle. 

Fletcher GG, Rossetto FE, Turnbull JD, et al. 1994. Toxicity, uptake, and mutagenicity of particulate and soluble nickel compounds. Environ Health Perspect 102(suppl 3) 69-79. 

Principles of skeletal structure formation of Raney catalysts are discussed, first from the perspective of phase transformation by chemical leaching. Some ideas are then proposed for making new Raney catalysts. Rapid solidification and mechanical alloying (MA) are described as potential processes for preparing particulate precursors. A rotating-water-atomization (RWA) process developed by the author and co-workers is shown as an example of rapid solidification. 

Alfheim, I., G. Lofroth, and M. Moller, Bioassay of Extracts of Ambient Particulate Matter, Environ. Health Perspect., 47, 227-238 (1983). 

Barale, R., L. Giromini, S. Del Ry, B. Barnini, M. Bulleri, I. Barrai, F. Valerio, M. Pala, J. He, Chemical and Mutagenic Patterns of Airborne Particulate Matter Collected in 17 Italian Towns, Environ. Health Perspect., 102, 67-73 (1994). 

Pbrera, F.P. (1981). Carcinogenicity of airborne fine particulate benzo[a]py-rene an appraisal of the evidence and the need for control Environ. Health Perspect. 42,163. 

Ostro B, Tobias A, Querol X, Alastuey A, Amato F, Pey J, Perez N, Sunyer J (2011) The effects of particulate matter sources on daily mortality a case-crossover study of Barcelona, Spain. Environ Health Perspect 119(12) 1781—1787... 

Morawska and co-workers have produced a number of review articles on this topic. For example, Holmes and Morawska [20] reviewed several simple and complex models covering a wide range of urban scales for the dispersion of particulate matter. Morawska et al. [21] focused on vehicle produced ultrafine particles and discussed limitations of measurement methods, sources, characteristics, transport and exposure of these particles in urban environments. Their further review focused on indoor and outdoor monitoring of airborne nanoparticles [3]. Morawska [22] discussed the importance of airborne ENPs from the health perspective. Regulations and policy measures related to the reduction of ambient particulate matter were discussed in their follow-up article [23], Their recent review article discussed the commuters exposure to ultrafine particles and associated health effects [24]. 

Keil, R. G.,Tsamakis, E., and Hedges, J. I. (2000). Early diagenesis of particulate amino acids in marine systems. In Perspectives in Amino Acid and Protein Geochemistry, Goodfriend, G. A., Collins, M. J., Fogel, M. L., Macko, S. A., and Wehmiller, J. E, eds., Oxford University Press, New York, pp. 69-82. 

Dejmek J, Selevan SG, Benes I, Solansky I, Sram RJ (1999) Fetal growth and maternal exposure to particulate matter during pregnancy. Environ Health Perspect, 107(6) 475-480. 

Glinianaia S, Rankin J, Bell R, Pless-Mulloli T, Howel D (2004) Does particulate air pollution contribute to infant death Environ Health Perspect, 112(14) 1365-1370. 

Rivers transport material in several phases dissolved, suspended particulate and bed load. Physical and chemical processes within an estuary infiuence the transportation and transformation of this material, thereby affecting the net supply of material to the oceans. Several definitions and geomorphologic classifications of estuaries have been reviewed by Pe-rillo (1995). From a chemical perspective, an estuary is most simply described as the mixing zone between river water and seawater characterised by sharp gradients in the ionic strength and chemical composition. Geographic distinctions can be made between drowned river valleys, fjords and bar-built estuaries. They can alternatively be classified in terms of the hydrodynamic regime as ... 

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