In ...... process,work is done at the expense of internal energy.

What is the change in internal energy when a system releases $8 \ kJ$ of heat and performs $660 \ J$ of work on the surroundings (in $J$)?

$A$ sample of gas absorbs $4000 \ kJ$ of heat and the surrounding does $2000 \ J$ of work on the sample. What is the value of $\Delta U$ (in $kJ$)?

What is the work done during the oxidation of $4 \ mol$ of $SO_{2(g)}$ to $SO_{3(g)}$ at $27^{\circ} C$ (in $kJ$)? $(R = 8.314 \ J \ K^{-1} \ mol^{-1})$

Calculate the change in internal energy of the system if $25 \ kJ$ of work is done by the system and it absorbs $10 \ kJ$ of heat. (in $kJ$)

For the reaction $C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(l)$,the value of $\Delta H - \Delta U$ is: