The molar internal energy of a gas at temperature T is Um (T). The mo ...
Explanation:
The molar internal energy of a gas at temperature T is Um (T). The molar internal energy at T = 0 is Um (0). The correct expression that relates these two with appropriate contributions is:
Option B: Um(T) = Um(0) + 5/2 RT [linear molecule; translation and rotation only]
Explanation:
For a linear molecule, the internal energy is contributed by translation and rotation only. Therefore, the molar internal energy of a gas at temperature T for a linear molecule can be expressed as:
Um(T) = Um(0) + NfRT
where N is the number of moles of gas, f is the degree of freedom, and R is the gas constant.
For a linear molecule, the degree of freedom is 5, which includes 3 degrees of freedom for translation and 2 degrees of freedom for rotation. Therefore, the expression for the molar internal energy becomes:
Um(T) = Um(0) + 5/2 RT
This is the correct expression that relates the molar internal energy of a gas at temperature T and T=0 for a linear molecule with appropriate contributions.
Conclusion:
Hence, the correct option is B.
The molar internal energy of a gas at temperature T is Um (T). The mo ...
We know (dU/dT)v=Cv. so, dU=CvdT. Um(T)-Um(0)=CvT. And Cv=5/2 RT. Um(T)-Um(0)=5/2 RT. But I am not confirm about the ans. please tell me it is right or not.