What is the change in internal energy if a system does $140 \ kJ$ of work on the surroundings and $40 \ kJ$ of heat is added to the system (in $kJ$)?

$A$ gas absorbs $150 \ J$ of heat and expands by $300 \ cm^3$ against a constant external pressure of $2 \times 10^5 \ N \ m^{-2}$. What is the change in internal energy $(\Delta U)$ of the system (in $J$)?

$A$ sample of liquid in a thermally insulated container (a calorimeter) is stirred for $2 \ hr$ by a mechanical linkage to a motor in the surroundings. For this process:

For the reaction $C_2H_5OH_{(l)} + 3O_{2(g)} \rightarrow 2CO_{2(g)} + 3H_2O_{(l)}$,the enthalpy change $(\Delta H)$ at $27\,^oC$ is $-1366.5 \,kJ\,mol^{-1}$. What will be the value of the internal energy change $(\Delta U)$ in $kJ\,mol^{-1}$ at the same temperature?

One mole of a gas absorbs $200 \ J$ of heat at constant volume. Its temperature increases from $298 \ K$ to $308 \ K$. The change in its internal energy is ....... Joules.

Assuming that water vapour is an ideal gas,the internal energy change $(\Delta U)$ when $1\, mol$ of water is vaporised at $1\, bar$ pressure and $100\, ^{\circ}C$,(given: molar enthalpy of vaporisation of water at $1\, bar$ and $373\, K = 41\, kJ\, mol^{-1}$ and $R = 8.3\, J\, mol^{-1}\, K^{-1}$) will be .............. $kJ\, mol^{-1}$