For the reaction $N_{2(g)} + 3H_{2(g)} \rightarrow 2NH_{3(g)}$ at $298 \ K$,the enthalpy change $(\Delta H)$ is $-92.38 \ kJ$. What will be the internal energy change $(\Delta U)$ at $298 \ K$ in $kJ$?

For water $\Delta_{vap} H = 41 \ kJ \ mol^{-1}$ at $373 \ K$ and $1 \ bar$ pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water,the internal energy change during evaporation of water is $...... \ kJ \ mol^{-1}$.
[Use: $R = 8.3 \ J \ mol^{-1} \ K^{-1}$]

$A$ system is provided with $50 \ J$ of heat and the work done on the system is $10 \ J$. What is the change in internal energy of the system in joules?

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

Two litres of an ideal gas at a pressure of $10 \ atm$ expands isothermally at $25^{\circ}C$ into a vacuum until its total volume is $10 \ litres$. How much heat is absorbed and how much work is done in the expansion?

The work done to contract a gas in a cylinder is $462 \, J$. $128 \, J$ of energy is evolved in the process. What will be the internal energy change in the process? (in $J$)