A piston-cylinder device contains 1 kmol of ammonia (NH3, molecular weight 17 kg

Question

A piston-cylinder device contains 1 kmol of ammonia (NH3, molecular weight 17 kg/kmol). The piston weighs 100 kg with a surface area of 0.01 m2, and the ambient pressure is 1 bar. Initially the system is at equilibrium with the volume of 6 m3. The system undergoes a process during which pV=constant and the volume is reduced to half. Find the following:

(a) the final pressure = _______________ (b) the final specific volume = ________________
(c) the work output = _________________
(d) sketch the p-V diagram with detailed labels of the initial and final states and corresponding p and V data.

Explanation / Answer

a) p1v1 = p2v2

now if v2 = v1/2

p2 = 2p1

now,

mg = Ap

100 x 10 x 9.8 = 0.01 x (p1 - 105]

p1 = 880000 pa = 880 kPa

p2 = 1760 kPa

b) V = 6/17 = 0.353 m3/kg

c) W = nRTln(V2/V1) = 1000 x 8.314 x (p1v1/nR) x ln(1/2)

W = -415888.3 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.