Calculate the change in internal energy of the system if work done by the system is $18 \ J$ and absorbs heat $50 \ J$ in a particular reaction. (in $J$)

For the reaction $N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)$ at constant temperature and pressure,if $\Delta H$ and $\Delta U$ are the enthalpy and internal energy changes for the reaction,which of the following equations is correct?

An engine absorbs heat $Q_1$ at temperature $T_1$ and heat $Q_2$ at temperature $T_2$. The work done by the engine is given as $W = Q_1 + Q_2$. Which of the following statements is correct?

Internal energy of an ideal gas increases in:

Derive the relationship between $\Delta H$ and $\Delta U$ for an ideal gas. Explain each term involved in the equation.

Calculate $\Delta H$ for the following reaction at $25^{\circ} C$.
$NH_2CN_{(g)} + \frac{3}{2} O_{2_{(g)}} \longrightarrow N_{2_{(g)}} + CO_{2_{(g)}} + H_2O_{(l)}$
$(\Delta U = -740.5 \ kJ, R = 8.314 \ J \ K^{-1} \ mol^{-1})$