Question

Neon is compressed from 100 kPa and 16°C to 500 kPa in an isothermal compressor. Determine the change in the specific volume and specific enthalpy of neon caused by this compression. The gas constant of neon is R = 0.4119 kJ/kg·K, and the constant-pressure specific heat of neon is 1.0299 kJ/kg·K.

Answer 1

Answer:

$\Delta v=-0.952m^3/kg$

$\Delta h=0$

Explanation:

In this case, since neon could be considered as an ideal gas, the specific volumes at the first and second state are respectively:

$v_1=\frac{Rg*T_1}{p_1}=\frac{0.4119kJ/kg*K*289.15}{100kPa} =1.19m^3/kg$

$v_2=\frac{Rg*T_2}{p_2}=\frac{0.4119kJ/kg*K*289.15}{500kPa} =0.238m^3/kg$

Thus, the change in the specific volume turns out:

$\Delta v=v_2-v_1=0.238m^3/kg-1.19m^3/kg\\\Delta v=-0.952m^3/kg$

Which value has sense for the compression.

In addition, the specific enthalpy change just depend on the temperature as it is an ideal gas, therefore, since the process es isothermic:

$\Delta h=Cp\Delta T=0$

Best regards.