One tenth kilogram of Argon is contained in a piston-cylinder assembly. Initially at 4900 K and a volume of 40 liters, the gas undergoes an isobaric process during which the heat input is 30 kJ. Where / how do i start to determine the boundary work and final temperature

100 kg of Ar is 2.5 moles. The pressure P can be obtained from that and the ideal gas law.
P = n R T/V = 2.5 moles*8.205*10^-2 l-atm/mole K * 4900 K/40 l = 25.1 atm = 25.4*10^5 N/m^2
Constant pressure heating of Ar will have a specific heat of (5/2) R. Use that info to obtain the final temperature, T2.
Get the final volume from
V2/V1 = T2/T1
Get the work done from P*(V2-V1)

drwls ...thanks for the help you have steered me in the right direction Gary