Answer:
[tex]\Delta S=-0.11\frac{kJ}{kg*K}[/tex]
Explanation:
Hello,
In this case, we can compute the entropy change by using the following equation containing both pressure and temperature:
[tex]\Delta S=Cp\ ln(\frac{T_2}{T_1} )-R\ ln(\frac{p_2}{p_1} )[/tex]
Thus, we use the given data to obtain (2 MPa = 2000 kPa):
[tex]\Delta S=0.846\frac{kJ}{kg*K} \ ln(\frac{800K}{400K} )-0.1889\frac{kJ}{kg*K} \ ln(\frac{2000kPa}{50kPa} )\\\\\Delta S=-0.11\frac{kJ}{kg*K}[/tex]
Best regards.