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Homework 9.13

Posted: Sat Mar 18, 2017 9:42 pm
by Michael_Phillipi_1I
The problem states "During the test of an internal combustion engine, 3.00 L
of nitrogen gas at 18.5 C was compressed suddenly (and
irreversibly) to 0.500 L by driving in a piston. In the process,
the temperature of the gas increased to 28.1 C. Assume ideal
behavior. What is the change in entropy of the gas?"

However, when finding the change in entropy with the change in temperature, Cv of an ideal gas is not used, R is used. The solutions manual says "assume ideal behavior." Why do you not use Cv = (3/2)R?

Re: Homework 9.13

Posted: Sat Mar 18, 2017 10:37 pm
by Alexander_Chang_1I
The problem states that the reaction is irreversible. The equation you are thinking of is only used when the reaction is reversible and isothermal.