The internal energy change (in $J$) when $90 \ g$ of water undergoes complete evaporation at $100^{\circ} C$ is........
(Given: $\Delta H_{vap}$ for water at $373 \ K = 41 \ kJ/mol$,$R = 8.314 \ J \ K^{-1} mol^{-1}$)

Which of the following relations between enthalpy change $(\Delta H)$ and internal energy change $(\Delta U)$ is correct for the given reactions?

For the reaction $A_{(g)} + 2B_{(g)} \to 2C_{(g)} + 3D_{(g)}$,the value of $\Delta E$ at $27\ ^oC$ is $19.0\ kcal$. The value of $\Delta H$ for the reaction would be.......$kcal$ $(R = 2.0\ cal\ K^{-1} mol^{-1})$

The values of $\Delta H$ for the combustion of ethene and ethyne are $-341.1 \ kcal$ and $-310.0 \ kcal$ respectively. Which of the following is a better fuel?

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 $K$?

For the following reaction occurring in automobiles,the values of $\Delta H, \Delta S, \text{and } \Delta G$ are respectively:
$2C_8H_{18(g)} + 25O_2(g) \rightarrow 16CO_2(g) + 18H_2O(g)$