For the process $CO_2(s) \rightarrow CO_2(g)$,which of the following is true?

For a massless piston undergoing an expansion of $\Delta V$ at constant temperature against a variable external pressure $P$,which equation represents the work done?

The amount of heat measured for a reaction in a bomb calorimeter is

Although heat is a path function,heat absorbed by the system under certain specific conditions is independent of path. What are those conditions? Explain.

The enthalpy change $(\Delta H)$ for the reaction,$N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}$ is $-92.38 \ kJ$ at $298 \ K$. The internal energy change $\Delta U$ at $298 \ K$ is .............. $kJ$

Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be .............. $Joules$.