0.2 kg of air is heated in a constant volume process from 20 to 100(degrees celsius). The specific heat at constant volume is 0.7186J/ Kg K. Calculate the change in entropy of this process.

Respuesta :

Answer:

[tex]\delta \ S =0.034679 \ J/K[/tex]

Explanation:

The formula for calculating the change in  entropy of a process can be expressed as:

[tex]\delta \ S = \int\limits \ \frac{d \theta }{T}[/tex]

[tex]\delta \ S = mc \int\limits^{T_2}_{T_1} \ \frac {d T}{T}}[/tex]

[tex]\delta \ S = mc \ In (T) ^{T_2}_{T_1}[/tex]

[tex]\delta \ S = mc \ [In \ (T_2) - In \ ({T_1})][/tex]

[tex]\delta \ S = mc \ In \ (\frac{T_2}{T_1})[/tex]

Given that:

mass m = 0.20 kg

specific heat constant c  =  0.7186J/ Kg K

[tex]T_2[/tex] = 100° C = ( 100 + 273.15) = 373.15 K

[tex]T_1[/tex] = 20° C = ( 20  + 273.15) = 293.15 K

Replacing our values into above equation; we have :

[tex]\delta \ S = (0.20)(0.7186) \ In \ (\frac{373.15}{293.15})[/tex]

[tex]\delta \ S =0.034679 \ J/K[/tex]