A gas is allowed to expand against a constant external pressure of 2.5 bar from an initial volume 'x' L to final volume of 4.5 L. If amount of work done is 5 dm$$^3$$ bar, what is the value of 'x'?

In a process, a system performs $$238 \mathrm{~J}$$ of work on it's surrounding by absorbing $$54 \mathrm{~J}$$ of heat. What is the change in internal energy of system during this operation?

When $$\mathrm{x} \mathrm{kJ}$$ heat is provided to a system, work equivalent to $$\mathrm{y} \mathrm{J}$$ is done on it. What is internal energy change during this operation?

What is the constant external pressure of an ideal gas when expanded from $$2 \times 10^{-2} \mathrm{~m}^3$$ to $$3 \times 10^{-2} \mathrm{~m}^3$$, if the work done by the gas is $$-5.09 \mathrm{~kJ}$$ ?