At constant pressure, the work done for gas to expand is given by:
W = PΔV
⇒W = 1.65 × 10⁵Pa × (0.320 – 0.110)m³= 3.46 × 10⁴J
The total heat (Q) added to the system is used in work done and the remaining energy goes into internal energy.
ΔU = ΔQ-ΔW
⇒ΔU = 1.15 ×10⁵J – 3.46 × 10⁴J = 0.8 × 10⁵ J
It does not matter that the gas is ideal or real because the work done would remain same. It would vary for real gases only at very high pressure.