posted by Nick .
An ideal gas (volume 1.1m3, pressure 103600 Pa, temperature 400 K) undergoes an isothermal process during which it absorbs 2000 J of heat. How much did the entropy of the system increase?
delta S = Qin/T = 2000/500 = 4.0 J/K
You don't need to use the pressure or (initial) volume