Isothermal expansion and final pressure

[jimbo71]

Homework Statement

a monatomic ideal gas(Cv=3/2R) undergoes an isothermal expansion at 300K, as the volume increased from 0.09m^3 to 0.36m^3. the final pressure is 100kPa. the change in the internal energy of the gas, in kJ is closest to
a. 0
b. 25
c. -50
d. -25
e. 50

Homework Equations

Q=W

The Attempt at a Solution

I think because it is an isothermal process the internal energy of an ideal gas depends only on the temperature. since the temperature remains the same wouldn't the internal energy be zero.

 

[rl.bhat]

That is right.

 

[thomate1]

Therefore, the closest answer would be a. 0. This is because in an isothermal process, the temperature remains constant and thus the internal energy remains constant as well. The change in internal energy would be zero as no work is done on or by the gas, and no heat is exchanged with the surroundings. Therefore, the final pressure does not affect the change in internal energy and it remains at zero.