First law of thermodynamics! Simple yet complex question

[bianca1992]

Hi all I am really struggling with my worked example at my placement. Please help! My answers are awfully wrong.

A pump compressing hydrogen from a low pressure to a high pressure tank where the tanks pressure is constant and H2 is an ideal gas.
Hydrogen: (H2: MW = 2, Cv = 10 kJ/kgK)
Low pressure tank: (P = 4 bar, T = 30oC)
High pressure tank: (P = 100 bar).

1) Apply the first law of thermodynamics eliminating terms not needed
2) Find the compressor outlet temp when the compression goes along an adiabatic and polytrophic process

[zeke]

dQ=CvdT+PdV energy equation statement of 1st Law
PdV+VdP=nRdT-= gas law
Next prove
Cp=Cv+nR

Now from these you should be able to get
PV^k= constant when dQ=0
k=Cp/Cv

I gave you more than I should have to get you started
Now you do the rest of your homework..