A property of a
system that is determined by the
state or condition of the system and not by how it got to that state; its value is fixed when
temperature,
pressure,
composition, and physical form are specified.
A state function, then, is a
function that is dependent on
state variables. A
state variable is a characteristic that defines the set of
conditions a given
system is under. For example,
temperature and
pressure are both variables that you are likely to find in a state function.
Chemistry includes state functions such as the equations for pressure, volume, temperature, enthalpy, entropy, etc.