Find work done on 2 mole of an ideal gas at $27^{\circ} \mathrm{C}$ if it is compressed reversibly and isothermally from $5.05 \times 10^6 \mathrm{Nm}^{-2}$ to $1.01 \times 10^5 \mathrm{Nm}^{-2}$ pressure.

A system performs mechanical work equal to 15 kJ and looses 2 kJ of heat to surrounding. What is the change in internal energy of a system?

Find the constant external pressure required to expand a gas from 2.5 L to 4.5 L if amount of work done is 500 J at 298 K ?

In a particular reaction ' x ' kJ of heat is released by the system and ' y ' kJ of work done is done on the system. What is internal energy change?