Question

The first law of thermodynamics can be stated in the form $\Delta U=\Delta Q+\Delta W\Delta U$ is the increase in the internal energy of the system; $\Delta Q$ is the heat supplied to the system; $\Delta W$ is the external work done on the system. Which of the quantities $\Delta U,\Delta Q$ and $\Delta W$ are necessarily zero when the system is an ideal gas that undergoes a change at constant temperature?.

• A. $\Delta U$ only
• B. none of $\Delta U,\Delta Q,\Delta W$
• C. $\Delta Q$ only
• D. all of $\Delta U,\Delta Q,\Delta W$

Answer 1

Answer: (A)

$\Delta U=n{C}_{\nu }\Delta T=0$ if $\Delta T=0$.