What is substance in thermodynamics ?



In
thermodynamics a working substance is defined as a fluid (liquid or gas) in
which energy can be stored, removed or transferred through.

Example Air
in IC engine, steam in boiler, water in hydraulic turbine.




Pure
substance


A pure
substance needs to be –

1. Homogeneous in composition (i.e. single
chemical species)

2. Homogeneous and invariable in chemical
aggregation (i.e.

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