Calculate the change in enthalpy in a chemical reaction when work done is $-800 \ J$ and increase in internal energy is $600 \ J$. (in $J$)

Which of the following is the correct option for the free expansion of an ideal gas under adiabatic conditions?

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?

Which of the following is not equal to zero in a cyclic process?

For the reaction $C_{(s)} + \frac{1}{2}O_{2(g)} \to CO_{(g)}$ at constant $T$ and $P$,which of the following statements is correct?

$A$ system absorbs $600 \ J$ of heat and does work equivalent to $300 \ J$ on its surroundings. The change in internal energy is ...... $J$.