In the reaction at $300 \ K$:
$C_6H_6(\ell) + \frac{15}{2}O_{2(g)} \to 6CO_{2(g)} + 3H_2O(\ell) \quad \Delta H = -3271 \ kJ$
What is the value of $\Delta U$ for the combustion of $1.5 \ mol$ of benzene at $27 \ ^oC$? $..... \ kJ$

$1.8 \ g$ of water is vaporized by supplying $4 \ kJ$ of heat at $100^{\circ}C$. What is the molar heat of vaporization of water at the same temperature?

$A$ swimmer coming out from a pool is covered with a film of water weighing about $18 \ g$. How much heat must be supplied to evaporate this water at $298 \ K$? Calculate the internal energy of vaporisation at $298 \ K$. Given: $\Delta_{vap} H^{\ominus}$ for water at $298 \ K = 44.01 \ kJ \ mol^{-1}$.

For the reaction $2C_6H_6(l) + 15O_2(g) \rightarrow 12CO_2(g) + 6H_2O(l)$ at $25 \ ^\circ C$,calculate the difference between the heat of reaction at constant volume and constant pressure in $kJ$.

The standard entropies of $X_2$,$Y_2$,and $XY_3$ are $60$,$40$,and $50 \ J \ K^{-1} \ mol^{-1}$ respectively. For the reaction $\frac{1}{2}X_2 + \frac{3}{2}Y_2 \to XY_3$,$\Delta H = -30 \ kJ$ at equilibrium. What is the temperature of the system in $K$?

Calculate the standard internal energy change for $OF_{2(g)} + H_2O_{(g)} \longrightarrow 2 HF_{(g)} + O_{2(g)}$ at $300 \ K$,if $\Delta_{f} H^{\circ}$ of $OF_{2(g)}$,$H_2O_{(g)}$,and $HF_{(g)}$ are $20$,$-250$,and $-270 \ kJ \ mol^{-1}$ respectively. $[R = 8.314 \ J \ K^{-1} \ mol^{-1}]$ (in $kJ$)