Question:
What do trends in the periodic table and specific heat
have to do with one another?
Replies:
There is no overarching connection because the elements of the periodic
table are gases, liquids, and solids. In general, the molar heat capacity
of gases is smaller than either solids or liquids. The molar heat capacity
of solids is less than liquids particularly if the temperature is well
below the melting point. Near the melting point the molar heat capacity of
the liquid and solid can go either way depending upon the element.
As one moves down a column of the periodic table the molar heat capacity
tends to increase (a mass effect); however, if the crystal structure of the
elements are different this trend may not hold. It is not useful to compare
specific heats, which are measured in calories or joules per gram. The
correct comparison is on a molar basis. Heat capacity is a very complicated
property of substances so caution must be used in comparing trends. That
applies to both elements and compounds.
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