Calculate the internal energy change of a system if the work done by the system is $8 \ J$ and the heat supplied to it is $40 \ J$. (in $J$)

When a gas undergoes adiabatic expansion,it cools down because:

$A$ heat engine absorbs heat $Q_1$ at temperature $T_1$ and heat $Q_2$ at temperature $T_2$. Work done by the engine is $(Q_1 + Q_2)$. This data

Two moles of an ideal gas are allowed to expand from a volume of $10 \ dm^3$ to $2 \ m^3$ at $300 \ K$ against a pressure of $101.325 \ kPa$. Calculate the work done. (in $kJ$)

$2.5 \ kJ$ of work is done on the system and it releases $1500 \ J$ of heat. What is the change in internal energy (in $J$)?

During the free expansion of an ideal gas,its.......