Argon is compressed in a polytropic process with n = 1.2 from 100 kPa and 30°C to 1200 kPa in a piston–cylinder device. Determine the final temperature of argon.

Respuesta :

Answer:

181 °C

Explanation:

Initial pressure [tex]P_{1}[/tex] = 100 kPa

Initial temperature [tex]T_{1}[/tex] = 30 °C = 30 + 273 K = 303 K

Final pressure [tex]P_{2}[/tex] = 1200 kPa

Final temperature [tex]T_{2}[/tex] = ?

n = 1.2

For a polytropic process, we use the relationship

([tex]T_{2}[/tex]/[tex]T_{1}[/tex] ) = ([tex]P_{2}[/tex]/[tex]P_{1}[/tex])^γ

where γ = (n-1)/n

γ = (1.2-1)/1.2 = 0.1667

substituting into the equation, we have

([tex]T_{2}[/tex]/303) = (1200/100)^0.1667

[tex]T_{2}[/tex]/303 = 12^0.1667

[tex]T_{2}[/tex]/303 = 1.513

[tex]T_{2}[/tex] = 300 x 1.513 = 453.9 K

==> 453.9 - 273 = 180.9 ≅ 181 °C