Change in internal energy of a gas

[6021023]

Homework Statement

Two moles of carbon monoxide (CO) start at a pressure of 1.2 atm and a volume of 30 liters. The gas is then compressed adiabatically to 1/3 this volume. Assume that the gas may be treated as ideal.

What is the change in the internal energy of the gas?

n = 1.2 atm
V2 = 10L
V1 = 30L
Cp = 29.16 J/(mol * K)

Homework Equations

Q = dU + W

The Attempt at a Solution

dU = dQ - dW
dU = nCpdT - pdV

dT is not known, and I can't go any further.

 

[Confundo]

You can find T_1 using PV = nRT. You can then use the adiabatic equation TV^{\gamma}= constant to find T_2