Matter Physical State and Chemical Constitution

The top beaker contains a solid with a molecular view of the solid the molecular view depicts the closely packed, immobile atoms that make up the solid structure.The middle beaker contains a liquid with a molecular view of the liquid the molecular view depicts atoms that are close together but moving freely.The bottom beaker contains a gas with a molecular view of the gas the molecular view depicts atoms that are far apart and moving freely. 

We describe iron as a silvery-colored metal that melts at 1535°C (2795°F). Once we have collected enough descriptive information about many different kinds of matter, patterns emerge that suggest ways of classifying it. ThCTe are two principal ways of classifying matter by its physical state as a solid, liquid, or gas and by its chemical constitution as an element, compound, or mixture. 

What distinguishes a gas from a liquid is the characteristic of compressibility (and its opposite, expansibility). A gas is easily compressible, whereas a liquid is not. You can put more and more air into a tire, which increases only sUghtly in volume. In fact, a given quantity of gas can fill a container of almost any size. A small quantity would expand to fill the container a larger quantity could be compressed to fill the same space. By contrast, if you were to try to force more liquid water into a closed glass bottle that was already full of water, it would burst. 

These two characteristics, rigidity (or fluidity) and compressibility (or expansibility), can be used to frame definitions of the three states of matter  

The term vapor is often used to refer to the gaseous state of any kind of matter that normally exists as a liquid or a solid. 

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Chemistry can be divided (somewhat arbitrarily) into the study of structures, equilibria, and rates. Chemical structure is ultimately described by the methods of quantum mechanics equilibrium phenomena are studied by statistical mechanics and thermodynamics and the study of rates constitutes the subject of kinetics. Kinetics can be subdivided into physical kinetics, dealing with physical phenomena such as diffusion and viscosity, and chemical kinetics, which deals with the rates of chemical reactions (including both covalent and noncovalent bond changes). Students of thermodynamics learn that quantities such as changes in enthalpy and entropy depend only upon the initial and hnal states of a system consequently thermodynamics cannot yield any information about intervening states of the system. It is precisely these intermediate states that constitute the subject matter of chemical kinetics. A thorough study of any chemical reaction must therefore include structural, equilibrium, and kinetic investigations. 

In the last few years much attention has been given to the evaluation of the elemental content of airborne particulate matter due to their detrimental effects on human health. Many epidemiological studies have revealed that the degree of adverse respiratory effects depends on the physical and chemical properties of atmospheric aerosol. The particulate matter with an aerodynamic diameter <10 pm (PMio) constitutes the inhalable fraction of aerosol, while the particulate matter with an aerodynamic diameter <2.5 pm (PM2.5) could have more serious toxic effects as it constitutes the breathable fraction of the aerosol. Under this framework, European Commission (EC) legislation requires that member states monitor the PMio and the lead concentration in atmosphere. " Furthermore the EC has recently proposed the monitoring of other toxic elements such as arsenic, cadmium and nickel in atmospheric particulate. ... 

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