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.