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An insulated rigid tank with a volume of 0.57 m3, contains 4 kg of Argon gas at 450 kPa and 30 C. A valve is now opened, and the Argon is slowly allowed to escape until the pressure inside drops to 200 kPa. Assuming the Argon remaining inside the tank has undergone a reversible, adiabatic process, determine the final mass in the tank,

Respuesta :

Answer:

The value is [tex]m_2 = 2.46 \ kg[/tex]

Explanation:

From the question we are told that

    The volume of the tank  is  [tex]V = 0.57 \ m^3[/tex]

    The mass of the Argon it contains is  [tex]m = 4 \ kg[/tex]

     The initial pressure on of the gas is  [tex]P_1 = 450 kPa = 450 *10^{3} \ Pa[/tex]

     The initial  temperature is  [tex]T_1 = 30^oC = 30 + 273 = 303 \ K[/tex]

     The  new pressure inside the tank is  [tex]P_2 = 200 \ kPa = 200 *10^{3} \ Pa[/tex]

Gnerally given that the  Argon remaining inside the tank has undergone a reversible, adiabatic process, then the final temperature of the Argon gas is mathematically represented as

             

      [tex]T_2 = T_1 * [\frac{P_2}{P_1} ]^{ \frac{(k - 1 )}{k} }[/tex]

Here k is the specific heat ratio of Argon with value [tex]k = 1.667[/tex]

So

         [tex]T_2 = 303 * [\frac{200}{450} ]^{ \frac{(1.667- 1 )}{1.667} }[/tex]

=>      [tex]T_2 = 219 \ K[/tex]

Generally from the ideal gas equation

        [tex]PV = mRT_2[/tex]

 So

      [tex]\frac{P_1V}{P_2V} =\frac{ m_1 * R * T_1 }{ m_2 * R * T_2}[/tex]

Here R is the gas constant with value  [tex]R = 8.314 \J \ K^{-1}\ mol^{-1}[/tex]

=>    [tex]m_2 = \frac{P_2 * T_1 }{ P_1 * T_2 } * m_1[/tex]

=>    [tex]m_2 = \frac{200 * 303 }{ 450 * 219 } * 4[/tex]

=>    [tex]m_2 = 2.46 \ kg[/tex]