An Overview of Physical States and Phase Changes

Imagine yourself among the particles of a molecular substance, HF, and you ll discover two types of electrostatic forces at work  

Now imagine a molecular view of the three states of water, as an example, and focus on just one molecule from each state. They look identical—bent, polar H—O—H molecules. In fact, the chemical behavior of the three states is identical because their molecules are held together by the same mrramolecular bonding forces. However, the physical behavior of the states differs greatly because the strengths of the mfe/rnolecular nonbonding forces differ greatly. 

In Table 12.1, we distinguish among the three states by focusing on three properties—shape, compressibility, and ability to flow. The following kinetic-molecular view of the three states is an extension of the model we used to understand gases (see Section 5.6)  

Stale Shape and Volume Compressibility Ability to Flow 

Gas Conforms to shape and volume of container High High 

Liquid Conforms to shape of container volume limited by surface Very low Moderate 

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An Overview of Physical States and Phase Changes Quantitative Aspects of Phase Changes... 

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