A rigid vessel contains 3.98 kg of refrigerant-134a at 700 kPa and 60°C. Determine the volume of the vessel and the total internal energy. m3 (Round to four decimal places) kJ (Round to one decimal place)

Respuesta :

Answer: The volume of the vessel is [tex]0.1542m^3[/tex] and total internal energy is 162.0 kJ.

Explanation:

  • To calculate the volume of water, we use the equation given by ideal gas, which is:

[tex]PV=nRT[/tex]

or,

[tex]PV=\frac{m}{M}RT[/tex]

where,

P = pressure of container = 700 kPa

V = volume of container = ? L

m = Given mass of R-134a = 3.98 kg = 3980 g    (Conversion factor: 1kg = 1000 g)

M = Molar mass of R-134a = 102.03 g/mol

R = Gas constant = [tex]8.31\text{L kPa }mol^{-1}K^{-1}[/tex]

T = temperature of container = [tex]60^oC=[60+273]K=333K[/tex]

Putting values in above equation, we get:

[tex]700kPa\times V=\frac{3980g}{102.03g/mol}\times 8.31\text{L kPa }\times 333K\\\\V=154.21L[/tex]

Converting this value into [tex]m^3[/tex], we use the conversion factor:

[tex]1m^3=1000L[/tex]

So, [tex]\Rightarrow (\frac{1m^3}{1000L})\times 154.21L[/tex]

[tex]\Rightarrow 0.1542m^3[/tex]

  • To calculate the internal energy, we use the equation:

[tex]U=\frac{3}{2}nRT[/tex]

or,

[tex]U=\frac{3}{2}\frac{m}{M}RT[/tex]

where,

U = total internal energy

m = given mass of R-134a = 3.98 kg = 3980 g  (Conversion factor: 1kg = 1000g)

M = molar mass of R-134a = 102.03 g/mol

R = Gas constant = [tex]8.314J/K.mol[/tex]

T = temperature = [tex]60^oC=[60+273]K=333K[/tex]

Putting values in above equation, we get:

[tex]U=\frac{3}{2}\times \frac{3980g}{102.03g/mol}\times 8.314J/K.mol\times 333K\\\\U=161994.6J[/tex]

Converting this into kilo joules, we use the conversion factor:

1 kJ = 1000 J

So, 161994.6 J = 162.0 kJ

Hence, the volume of the vessel is [tex]0.1542m^3[/tex] and total internal energy is 162.0 kJ.

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