A constant-volume tank contains $4.4$ $kg$ of air at $102$ $kPa$ and $309$${^\circ}C$. The air is cooled to the surroundings temperature of $28 {^\circ}C$. Assume constant specific heats at $300K$ ($C_v=0.718$ $kJ/Kg\cdot K$). Determine:
  1. the entropy change of the air in the tank during the process
  2. heat transfer to the surroundings
  3. entropy change of the surroundings
  4. entropy change of the universe

$\Delta S_{tank}=$ $kJ/kg\cdot K$

$Q=$ $kJ$

$\Delta S_{surr}=$ $kJ/kg\cdot K$

$\Delta S_{univ}=$ $kJ/kg\cdot K$

# Pay attention to the unit of each parameter