l. (2 pt) Which of the following equation is both physically and mathematically correct? Select all correct answers. 2. (4 pts.) A closed system consisting of 4 1b of a gas undergoes a process during which the relation between pressure and volume is PV" : const. The process begins with 131' : 15 lbf/inch2 , I91 : 1.25 ftS/lb and ends walla : 53 lbf/inchl, If; : 0.5 113/11; . Determine: (a) The volume, in ft3, occupied by the gas at both state 1 and 2 (i.e., V1 and V2); (b) The value of n; 3. (4 pts.) A gas contained within a closed piston-cylinder assembly undergoes three processes in series: Process 12: Constant volume from P1 : 1 bar, V1 : 4 m3 to state 2, where P2 : 2 bar; Process 2-3: Compression to V3 : 2 1113, during which the pressureevolume relationship is PV : constant; Process 3-4: Constant pressure to state 4, where V4 : 1 m3; (a) Sketch the processes in series on P-V coordinates. (b) Evaluate the magnitude of work in k] for EACH process. To make the unit consistent. you might need to convert the unit of pressure from bar to Pa