Ask Question
16 February, 15:06

100 kg of R-134a at 200 kPa are contained in a piston-cylinder device whose volume is 12.322 m3. The piston is now moved until the volume is one-half its original size. This is done such that the pressure of the R-134a does not change. Determine the final temperature and the change in the total internal energy of the R-134a.

+1
Answers (1)
  1. 16 February, 16:26
    0
    T=151 K, U=-1.848*10^6J

    Explanation:

    The given process occurs when the pressure is constant. Given gas follows the Ideal Gas Law:

    pV=nRT

    For the given scenario, we operate with the amount of the gas - n - calculated in moles. To find n, we use molar mass: M=102 g/mol.

    Using the given mass m, molar mass M, we can get the following equation:

    pV=mRT/M

    To calculate change in the internal energy, we need to know initial and final temperatures. We can calculate both temperatures as:

    T=pVM / (Rm); so initial T=302.61K and final T=151.289K

    Now we can calculate change of U:

    U=3/2 mRT/M using T - difference in temperatures

    U=-1.848*10^6 J

    Note, that the energy was taken away from the system.
Know the Answer?
Not Sure About the Answer?
Find an answer to your question ✅ “100 kg of R-134a at 200 kPa are contained in a piston-cylinder device whose volume is 12.322 m3. The piston is now moved until the volume ...” in 📘 Engineering if you're in doubt about the correctness of the answers or there's no answer, then try to use the smart search and find answers to the similar questions.
Search for Other Answers