Determine the work done and state the energy transfer

Question

Question 1:

In a closed system 0.3 kg of gas at 373 K is expanded isothermally and reversibly from 1MPa pressure to 200 kPa. Given that C_v = 718 j/kg K and R = 287 J/kg K

Determine

(i) The work done

(ii) State the energy transfer within this isothermal process explaining your answer.

(i)
p₁ = 1MPa
p₂ = 200kPa
V₁ = 0.3 kg
V₂ = ?

Question 2:

Determine the thermal efficiency of a 60 MW output steam turbine supplied with 100 bar and 400^oC steam. The steam exits turbine at 0.07 bar and dryness fraction 0.73. The flow rate of the steam is 45 kg/s.