4. (30%) An oxygen gas cylinder of 1 m³ is initially at 50 bar and 250 K. The cylinder
is connected to another cylinder of 1 m³ volume under evacuated. A valve between
the two cylinder is opened until the pressures in the cylinders equalize, please:
(a) Define the system and formulate the mass, energy, and entropy balance.
(b) Calculate the final temperature and pressure in each cylinder under isothermal
condition.
(c) Calculate the number of moles of gas in each cylinder.
Hint: $C_p^*$ of is 29.3 J/mol K, list all the assumptions to be made in the calculation.