Change of matter

The Russian atomist, Mikhail Vasilyevich Lomonosov (1711-1765 CE) believed that changes of matter were due to the motions of constituent particles. The particles consisted of elementa that contain no smaller bodies of different kinds. If a corpnscle (a small mass consisting of aggregates of elementa) consisted of the same elementa, it was homogeneous. If the components of the corpuscles were different elementa, the corpuscles were heterogeneous (50). 

The chemistry of the ancients, as expressed by the writers from Theophrastus to Pliny and Dioscorides, was thoroughly practical. Their theories of the origin and changes of matter were based on their interpretation of the four elements as constituents of matter, principally as formulated by Plato and Aristotle. 

This Separation of the Water from the Earth where Air existed and Fire was diffused, is only a successive change of Matter under this double form 63 which has caused Philosophers to say that Water is the whole foundation of the Work, without which the Earth could not be dissolved, corrupted, prepared, and that the Earth is the body in which the Humid Elements end, congeal and are burned, so to speak, to assumed a more noble existence. 

Transport phenomena modeling. This type of modeling is applicable when the process is well understood and quantification is possible using physical laws such as the heat, momentum, or diffusion transport equations or others. These cases can be analyzed with principles of transport phenomena and the laws governing the physicochemical changes of matter. Transport phenomena models apply to many cases of heat conduction or mass diffusion or to the flow of fluids under laminar flow conditions. Equivalent principles can be used for other problems, such as the mathematical theory of elasticity for the analysis of mechanical, thermal, or pressure stress and strain in beams, plates, or solids. 

Phase Transformation The change of matter from one state (solid, liquid, gas) to another is called phase transformation. Phase transformation occurs at definite temperature (m.p. b.p sublimation temp., etc.). 

Although chemists deal primarily with the chemical changes of matter, physical changes are also very important. In this section we will consider how the entropy of a substance depends on its temperature and on its physical state. 

The American Society of Rheology, which was founded in 1929, has defined rheology as the science of deformation and flow of matter. Deformation describes the change of matter in terms of shape or volume, or both. If the changes due to deformation are at least partly nonreversible, then matter flows. The full spectrum of possible types of deformation of liquid or solid matter is illustrated in Fig. 1. The gaseous state is usually not part of rheological investigations. 

Many changes of matter happen. An ice cube melts. Your bicycle s spokes rust. A red shirt fades. Water fogs a mirror. Milk sours. Scientists who study these and many other events classify them by two broad categories physical changes and chemical changes. 

Physical chemistry The behavior and changes of matter and the related energy changes Reaction rates, reaction mechanisms... 

Define a quantum of energy and explain how it is related to an energy change of matter. 

You are very familiar with the changing states of water—from vapor to liquid and to ice. What environmental conditions are related to these changes of matter When you remove ice from your freezer, it soon melts to water. When you boil vegetables in water, water vapor rises from the pot. From these observations, it is clear that temperature plays an important role in the changing of state of water, and indeed, of all matter. 

Journal of Research in Science Teaching 20 (1983), 825 Stavy, R. Children s conceptions of changes of matter From liquid (or solid) to gas. Journal of Research in Science Teaching 27 (1990), 247... 

As we examine the chemical changes of matter, we encounter a series of fundamental substances called elements. Elements cannot be broken down into other substances by chemical means. Examples of elements are iron,... 

---