Solve the all parts of given problem:
Problem: A system of ideal gas at low density has an initial pressure of 1.28 x 105 Pa and occupies a volume of 0.25m3. The slow addition of 200 calories of heat causes it to expand isobarically to a volume of 0.30m3.
Part A: Find the work done by the system in this process?
Part B: Find the change in internal energy of the gas?
Please help for the above problem, completely confused!! Show each steps if possible, Thanks.