At a certain temperature, $T(K)$, during a process, $500 \text{ J}$ is absorbed by the system and work of $200 \text{ J}$ is done by the system. Then the change in internal energy of the system is: (in $\text{ J}$)

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

Assuming all reactions occur in an open vessel,for which reaction will $\Delta H = \Delta U$?

If the initial internal energy of a system is $U_1$,and it absorbs $450 \ J$ of heat from the surroundings and performs $600 \ J$ of work,what will be the final internal energy of the system?

$C_2H_5OH(l) + 3O_2(g) \rightarrow 2CO_2(g) + 3H_2O(l)$. The enthalpy change $(\Delta H)$ for the above reaction at $27^{\circ}C$ is $-1366.5 \text{ kJ mol}^{-1}$. Calculate the internal energy change $(\Delta U)$ for the same reaction at this temperature.

$A$ 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 $kJ$)?