Chemistry microscopic perspective

James G. Anderson is Philip S. Weld Professor of Atmospheric Chemistry at Harvard University. He received his B.S. in physics from the University of Washington and his Ph.D. in physics-astrogeophysics from the University of Colorado. His research addresses three domains within physical chemistry (1) chemical reactivity viewed from the microscopic perspective of electron structure, molecular orbitals, and reactivities of radical-radical and radical-molecule systems (2) chemical catalysis sustained by free-radical chain reactions that dictate the macroscopic rate of chemical transformation in the Earth s stratosphere and troposphere and (3) mechanistic links between chemistry, radiation, and dynamics in the atmosphere that control climate. Studies are carried out both in the laboratory, where elementary processes can be isolated, and within natural systems, in which reaction networks and transport patterns are dissected by establishing cause and effect using simultaneous, in situ detection of free radicals, reactive intermediates, and long-lived tracers. Professor Anderson is a member of the National Academy of Sciences. 

Particulate 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. Also called the microscopic perspective. 

Instead of considering wettability from the above traditional perspective, let us look at it from the opposite side What if we can control wettability of a surface at microscopic length scales, perhaps actively New developments in surface chemistry and fabrication of self-assembled monolayers (SAMs see Chapter 7) have opened up precisely such a possibility. How can we take advantage of such opportunities ... 

Multi-Focus Graphics To help you develop a more complete understanding of the topic presented, Multi-Focus Graphics provide macroscopic, microscopic, and symbolic perspectives to portray various chemical concepts. The Twelfth Edition adds to these graphics an intermediate process that shows you where chemistry is occurring in problem solving, xxxvi... 

The Study of Chemistry The Macroscopic Perspective The Microscopic or Particulate... 

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 inteiiectuai power of chemistry often iies in the way it aiiows us to iook at a probiem (or a design) from a number of perspectives. Both the physicai and chemicai properties of substances can be considered at the macroscopic or microscopic (particuiate) ievei depending on the nature of the question or probiem being considered. In addition, we often need to use symbolic representations to designate what is happening in chemical systems, so ultimately there are three perspectives that we will find useful throughout this text. 

In Chapter 10, we treated intermolecular interactions in a series of examples, two particles at a time. As we expand our perspective from the microscopic view of individual molecules out toward the macroscopic limit, we rapidly reach a point where the particles are too numerous to treat their interactions with that same attention to detail. But this point is critical to our understanding of chemistry, because here is also where we first begin to glimpse the properties of bulk materials. 

Statistics will help us reduce the number of coordinates we follow. However, we must not forget the lessons of the molecular perspective. The potential energy function between two molecules is just as important when there are 10 molecules as when there are only two, because every pair of molecules will experience this same potential energy function. The goal of Physical Chemistry Thermodynamics, Kinetics, and Statistical Mechanics is to develop these methods and apply them to obtain the common laws of chemistry that describe how the macroscopic properties of matter are influenced by its microscopic structure. 

Since the uptake and evaporation of gaseous H2O molecules (water vapor) are very important as a microscopic process of cloud physics, many measurements and theoretical studies have been made from this viewpoint. From the perspective of atmospheric chemistry, it is worthy of study as a most fundamental process of uptake to the water surface among other many atmospheric molecules. 

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