The heat capacity C of an object, is the proportionality constant between the heat Q that the object absorbs or loses and the resulting temperature change DT of the object. That is,
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Where, Ti and Tf are the initial and final temperatures of the object. Heat capacity C is the unit of energy per degree or energy per Kelvin. The heat capacity C of, say, a marble slab used in a bun warmer is 179 cal/Co, which we could also be written as 749 J/K.
The word 'capacity' in this context is really misleading since it suggests as analogy with the capacity of a bucket to hold water. That analogy is false, and you should not think of the object as containing heat or being limited in its ability to absorb heat. Heat transfer can proceed without limit as long as the necessary temperature difference is maintained. The object may, of course, melt or vaporize during the process.
