Question

For isothermal expansion of an ideal gas, the correct combination of the thermodynamic parameters will be

• A. $?U = 0, Q=0, w ?
• B. $?U ?
• C. $?U = 0, Q?
• D. $?U = 0, Q?

Answer 1

Answer: (D)

$?U = 0, Q?

Answer 2

For isothermal expansion of an ideal gas $\Delta T=0$ From $\Delta U=n C _{v} \Delta T$, $\Delta U=0$ and, from $\Delta H=n C _{\rho} \Delta t=0$ From first law of thermodynamics, as $\Delta U=Q+W$ $\Delta U=0 \Rightarrow Q \neq 0$ and $W \neq 0$ $\therefore$ Parameters are $\Delta U=0, Q \neq 0 ; W \neq 0$ and $\Delta H=0$