A piston contains 270 moles of an ideal monatomic gas that initally has a pressu

Question

A piston contains 270 moles of an ideal monatomic gas that initally has a pressure of 2.74 Times 105 Pa and a volume of 4.4 m3. The piston is connected to a hot and cold reservoir and the gas goes through the following quasi-static cycle accepting energy from the hot reservoir and exhausting energy into the cold reservoir. The pressure of the gas is increased to 5.74 Times 105 Pa while maintaining a constant volume. The volume of the gas is increased to 11.4 m3 while maintaining a constant pressure. The pressure of the gas is decreased to 2.74 Times 105 Pa while maintaining a constant volume. The volume of the gas is decreased to 4.4 m3 while maintaining a constant pressure. It may help you to recall that Cv = 12.47 J/K/mole and Cp = 20.79 J/K/mole for a monatomic ideal gas. How much work is done by the gas during the first step?

Explanation / Answer

1. ?U = Q - W

at constant V; W = 0

?U = nCv?T

P1V1 = nRT1

(2.74x105)(4.4) = 270(8.314)T1

T1 = 537.07K

P2V2 = nRT2

(5.74x105)(4.4) = 270(8.314)T2

T2 = 1125.1K

?U = nCv?T = 270(12.47)(1125.1 - 537.07)

= 1979.84KJ = Q

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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