急！普通物理習題

在絕熱膨脹，pV^# = 常數

#為摩爾比熱容量，對於單原子氣體，# = 5/3

1. 用piVi = nRTi

(1.013 X 10^5)Vi = (1)(8.31)(300)

最初體積，Vi = 0.0246 m^3

2. piVi^(5/3) = pfVf^(5/3)

(1.013 X 10^5)(0.0246)^(5/3) = (4 X 1.013 X 10^5)Vf^(5/3)

最終體積，Vf = 0.0107 m^3

3. pfVf = nRTf

(4 X 1.013 X 10^5)(0.0107) = (1)(8.31)Tf

最終溫度，Tf = 522 K

4. 在絕熱過程，氣體所作的功 = -3/2 nR(Tf - Ti)

= -3/2 (1)(8.31)(522 - 300)

= -2.77 X 10^3 J