Which of the following expressions represents the first law of thermodynamics?

Two moles of an ideal monoatomic gas are allowed to expand adiabatically and reversibly from $300 \ K$ to $200 \ K$. The work done in the system is $... \ kJ$ $(C_V = 12.5 \ J/K/mol)$.

When $1 \, \text{mol}$ of a gas is heated at constant volume,the temperature increases from $298 \, K$ to $308 \, K$. If the heat supplied to the gas is $500 \, J$,which of the following statements is correct?

If a gas expands adiabatically from $1 \, L$ to $12 \, L$ against a constant external pressure of $0.75 \, atm$,the $\Delta U$ of the gas is .... $J$. (in $.9$)

For the reaction,$CO_{(g)} + \frac{1}{2} O_{2_{(g)}} \longrightarrow CO_{2_{(g)}}$,which of the following equations is $CORRECT$ at constant $T$ and $P$?

In a process,the work done by the system is equal to the change in its internal energy. Then the process will be ...........