An ideal gas expands isothermally and reversibly from $$10 \mathrm{~m}^3$$ to $$20 \mathrm{~m}^3$$ at $$300 \mathrm{~K}$$, performing $$5.187 \mathrm{~kJ}$$ of work on surrounding, calculate number of moles of gas used.

"The mass and energy both are conserved in an isolated system", is the statement of

The temperature of $32^{\circ} \mathrm{C}$ is equivalent to

A gas performs 0.320 kJ work on surrounding and absorbs 120 J of heat from the surrounding. Hence, change in internal energy is