What is the difference between $\Delta H$ and $\Delta U$ for the reaction given below at $298 \ K$ (in $kJ$)? $(R = 8.314 \ J \ K^{-1} \ mol^{-1})$
$2 \ C_6H_{6(\ell)} + 15 \ O_{2(g)} \rightarrow 12 \ CO_{2(g)} + 6 \ H_2O_{(\ell)}$

Which of the following statements is correct?

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?

Under isothermal condition,a gas expands from $0.2 \ dm^3$ to $0.8 \ dm^3$ against a constant external pressure of $2 \ bar$ at $300 \ K$. Find the work done by the gas. (in $J$)

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 expands isothermally against a constant external pressure of $1 \ bar$ from $10 \ dm^3$ to $20 \ dm^3$ by absorbing $800 \ J$ of heat from the surroundings. Calculate the value of $\Delta U$. (in $J$)