| Introduction
 
 
 This page relates to the physical factors affecting chemical processes..States of matter
 
 
 Matter exists mainly in three states gas, liquid and solid.  A material
such as water can exist as a gas (steam) a liquid (water) or a solid (ice).   Its state
results from its condition of temperature and pressure.
 A gas has no bounding surface it fills all of the space it occupies.   Its density is very much
related to the quantity of matter the temperature and the pressure.
 
 A liquid has no shape. It takes the shape of the vessel it occupies.   It does however
have a surface which limits the volume it occupies.   It is normally has a greater density than a gas.
Its volume and related density is affected to some extent by temperature and to a lesser effect
by pressure. Liquids are often assumed to be incompressible
 
 A solid has a fixed shape and its  volume changes by only a relative small amount
on changes of pressure and temperature.
 
 In normal conditions a solid can be converted to a liquid if its temperature is
raised to its melting point temperature and a liquid can be converted to a gas
if its temperature is raised to its evaporation tempature which is related to 
the local pressure..
 
 
 
 
 
 
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