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

The mathematical equation of the first law of thermodynamics for an isochoric process is:

At $300 \ K$,the enthalpy change for the reaction $C_3H_8(g) + 5O_2(g) \rightarrow 3CO_2(g) + 4H_2O(l)$ is $-2800 \ kJ \ mol^{-1}$. Calculate the internal energy change $(\Delta U)$ for the reaction at the same temperature.

Internal energy of an ideal gas increases in:

$A$ gaseous sample expands from $200 \, cm^3$ to $500 \, cm^3$ against a constant external pressure of $750 \, torr$ while absorbing $1.5 \, J$ of heat. What is the change in internal energy of the system in $J$? $(1 \, atm \cdot L = 101.3 \, J)$

During compression of a spring,the work done is $10 \ kJ$ and $2 \ kJ$ escaped to the surroundings as heat. The change in internal energy,$\Delta U$ (in $kJ$),is