Internal energy of an ideal gas increases in:

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

The $\Delta U^o$ of combustion of $CH_{4(g)}$ at a certain temperature is $-393 \ kJ/mol$. Then the value of $\Delta H^o$ is:

In a process,a system performs $238 \ J$ of work on its surroundings by absorbing $54 \ J$ of heat. What is the change in internal energy of the system during this operation (in $J$)?

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

Based on the first law of thermodynamics,which one of the following is correct?