For an isothermal process, the internal energy of a gas
A. Increases
B. Decreases
C. Remains unchanged
D. Data insufficient, can't be predicted
Answer: Option C
Solution(By Examveda Team)
The internal energy ($$U$$) is a function of$$dU = CvdT - \left[ {P + T\left\{ {\frac{{\left( {\frac{{\partial V}}{{\partial T}}} \right)p}}{{\left( {\frac{{\partial V}}{{\partial P}}} \right)T}}} \right\}dV} \right]$$
For an ideal gas, $$PV = RT$$
So, $$\left( {\frac{{\partial V}}{{\partial T}}} \right)p = \frac{R}{P}{\text{ and}}\left( {\frac{{\partial V}}{{\partial T}}} \right)T = \frac{{ - RT}}{{{P^2}}}$$
Hence, $$dU = CvdT$$
So, for an ideal gas if it undergoing isothermal change $$\left( {dT = 0} \right) \Rightarrow dU = 0$$
So, the questioned should be changed and should be mentioned for an ideal gas.
Related Questions on Chemical Engineering Thermodynamics
A. Maxwell's equation
B. Thermodynamic equation of state
C. Equation of state
D. Redlich-Kwong equation of state
Henry's law is closely obeyed by a gas, when its __________ is extremely high.
A. Pressure
B. Solubility
C. Temperature
D. None of these
A. Enthalpy
B. Volume
C. Both A & B
D. Neither A nor B
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