In this paper, we have deduced an analytic expression for the adiabatic compressibility

for a Chaplygin gas which is a function of the pressure P and temperature T. We have considered the work of Panigrahi (2015) for variable Chaplygin gas, exotic matter used in some cosmological theories whose equation of state is of the form

with

and n is a constant. The expression obtained for

was used for the determination of the value of the thermal capacity at constant pressure

for variable Chaplygin gas. It is predicted in this research the behaviour of the adiabatic compressibility

of Chaplygin gas in the limit of high and low pressure. We have found that the adiabatic compressibility

is function of the pressure and

when

and

if

as in the ideal gas and

is always positive with
n<0.
Adiabatic Compressibility, Chaplygin Gas, Cosmological Theories, Equation of State, Exotic Matter
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