An insulated piston-cylinder device initially contains $240$ $L$ of air at $123$ $kPa$ and $10 ^{\circ}C$. Air is now heated for $18$ $min$ by a $200$ $W$ resistance heater placed inside the cylinder. The pressure of air is maintained constant during this process. Assume a constant specific heat of $Cp = 1.02$ $kJ/kg\cdot K$).
Determine:
  1. the mass of the air inside the cylinder
  2. th electrical work done during this process
  3. the final temperature
  4. the entropy change in air

$m_{air}=$ $kg$

$W_e=$ $kJ$

$T_f=$ $K$

$\Delta S_{air}=$ $kJ/K$

# Pay attention to the unit of each parameter