Calculate the new pressure of the gas enclosed in a cylinder when it compressed from 5 L to 2 L at 1 atm and 300 K. The final temperature in this process is 500 K.

For a certain reaction, $\Delta H^0$ is $-345$ kJ and $\Delta S^0$ is $-123\ \text{JK}^{-1}$. At what temperature the change over from spontaneous to nonspontaneous will occur?

For a reaction to be spontaneous at all temperatures, the values of enthalpy change and entropy change should be

Find $\Delta n$ when 1 mol of each $\text{NH}_{3(g)}$ and $\text{HCl}_{(g)}$, reacts to form solid $\text{NH}_4\text{Cl}$.