$A$ 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 $J$)

For which of the following reactions is $\Delta H \neq \Delta U$?

What is the change in internal energy if a system gains $x \ J$ of heat and $y \ J$ of work is done on it?

When $1 \ mol$ of ice melts at $0 \ ^oC$ and a constant pressure of $1 \ atm$,the system absorbs $1440 \ cal$ of heat. If the molar volumes of ice and water are $0.0196 \ L$ and $0.0180 \ L$ respectively,calculate the change in internal energy $(\Delta U)$ of the system in $cal$.

Calculate the change in internal energy of the system if $37.6 \ J$ of work is done by the system with heat loss of $14.6 \ J$ (in $J$)?

What is the internal energy change when $62 \ J$ of work is done on the system and $128 \ J$ of heat is transferred to the surrounding (in $J$)?