What is the value of $\Delta H - \Delta U$ for the formation of $2$ moles of ammonia from $H_{2(g)}$ and $N_{2(g)}$?

For the reaction $PCl_{5(g)} \to PCl_{3(g)} + Cl_{2(g)}$,which of the following relations is correct?

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?

$A$ system performs mechanical work equal to $15 \ kJ$ and loses $2 \ kJ$ of heat to the surroundings. What is the change in internal energy of the system (in $kJ$)?

If $\Delta E$ is the heat of reaction for $C_2H_5OH_{(l)} + 3O_{2(g)} \longrightarrow 2CO_{2(g)} + 3H_2O_{(l)}$ at constant volume,the $\Delta H$ (heat of reaction at constant pressure) at constant temperature is

Which of the following statements is appropriate as per the first law of thermodynamics?