Problem 10.79 Challenge
หัวข้อ: กฎข้อที่หนึ่งของอุณหพลศาสตร์ (The First Law of Thermodynamics)
\(W = 573 J \;\blacksquare\)
ดูวิธีทำ
กำหนดให้ \(n = 2.00 mol, P_{1} = 100 kPa, T_{1} = 300 K\)
และ \(P_{2} = 120 kPa\)
a) จาก \(P_{1}V_{1} = nRT_{1}\)
\(V_{1} =\frac{nRT_{1}}{P_{1}}\)
\(V_{1} = 0.0499 m^{3} \;\blacksquare\)
\(_{\gamma\gamma}\)
b)จาก\(P_{1}V_{1}=P_{2}V_{2}\)
\(_{1/\gamma}\)
\(V_{2} = V_{1}(\frac{P_{1}}{P_{2}})\)
จาก \(c_{V}=\frac{d}{2}R=\frac{3}{2}R; d = 3\)
จาก \(c_{P}= c_{V}+R=\frac{5}{2}R\)
จาก \(\gamma =\frac{c_{P}}{c^{V}}=\frac{5}{3}\)
\(_{3/5}\)
จะได้ \(V_{2} = V_{1}(\frac{P_{1}}{P_{2}})\)
\(V_{2} = 0.0447 m^{3} \;\blacksquare\)
c) จาก \(P_{2}V_{2} = nRT_{2}\)
\(T_{2} =\frac{P_{2}V_{2}}{nR}\)
\(T_{2} = 323 K \;\blacksquare\)
d) จาก \(ΔU = nc_{V}\Delta T\)
\(\Delta U=n(\frac{3}{2}R)(T_{2}-T_{1}); c_{V}=\frac{3}{2}R\)
\(\Delta U = 573 J \;\blacksquare\)
e) จาก Adiabatic Process
\(\therefore Q = 0 J \;\blacksquare\)
f) จาก \(ΔU = Q + W\)
\(\Delta U = 0 + W; Adiabatic Process\)
\(W = \Delta U\)
\(W = 573 J \;\blacksquare\)