Physics: Change in internal Energy

Question

2.50 moles of an ideal monatomic gas are compressed from 315,000 Pa to 175,000 Pa at 0.0300 m3.

What is the change in internal energy in this isochoric process?

Answer 1

For a problem like this, there are two relevant equations:

 

1.) Ideal Gas Law: P*V=n*R*T

2.) Definition of Internal Energy: ΔU=n*c_v*ΔT

 

By finding the temperature of each gas state (initial and final pressure), you can find the change in temperature. Using this change of temperature, the change in internal energy can be calculated as c_v is approximately 1.5*R (where R is the ideal gas constant). Assume no work can be done by the gas due to the isochoric nature of this process, since ΔV=0.