Polytropic Process: Finding Final Pressure and Volume

[Mohd17]

Homework Statement

A frictionless piston cylinder contains ideal gas hydrogen , R = 4.125 KJ/Kg.K , initially at p1=100 Kpa , t1 = 765 C , V1 = 0.35 m3 . The gas undergoes a polytropic process with n = 1.22 until the final volume becomes V2=8.0 m3

Cp = 14.3338 , Cv= 10.2043 , [URL]http://www.taftan.com/thermodynamics/GAMMA.GIF[/URL] = 1.4

Find :
a) Mass of the ideal gas
b) Final pressure and volume of the gas

 

[rock.freak667]

You need to post your attempt.

What relevant equations do you think are needed here?

 

[Mohd17]

the problem how can i get the volume of the gas !

already i get the answers for part a and the final pressure

 

[rock.freak667]

the problem how can i get the volume of the gas !

already i get the answers for part a and the final pressure

You should know for a polytropic process PVⁿ = constant.

 

[Mohd17]

sorry but i didin't understand ...
now what's the answer ?

 

[rock.freak667]

sorry but i didin't understand ...
now what's the answer ?

PVⁿ = constant means that

P₁V₁ⁿ = P₂V₂ⁿ

You were given P₁, V₁, n and you found P₂.