When $6.0 \ g$ of graphite reacts with dihydrogen to give methane gas,$37.4 \ kJ$ of heat is liberated. What is the standard enthalpy of formation of $CH_{4(g)}$?

The enthalpies of combustion of rhombic and monoclinic sulfur are $70,960 \ cal$ and $71,030 \ cal$ respectively. The enthalpy of transition of rhombic sulfur to monoclinic sulfur is ...... $cal$.

The heats of hydrogenation for $3-$-methylbutene and $2-$-pentene are $-30\, kcal/mol$ and $-28\, kcal/mol$ respectively. The heats of combustion of $2-$-methylbutane and pentane are $-784\, kcal/mol$ and $-782\, kcal/mol$ respectively. All the values are given under standard conditions. Taking into account that combustion of both alkanes gives the same products,what is $\Delta H$ (in $kcal/mol$) for the following reaction under same conditions?
$3-$-methylbutene $\rightleftharpoons$ $2-$-pentene

Which of the following equations is correct for the heat of sublimation?

From the given data at $298 \, K$:
$\Delta H_f^o [CO_2, g] = -394 \, kJ/mol$
$\Delta H_f^o [H_2O, l] = -286 \, kJ/mol$
$\Delta H_f^o [propene, g] = 20 \, kJ/mol$
$cyclopropane (g) \to propene (g)$; $\Delta H^o_{isomerisation} = -33 \, kJ/mol$.
Calculate $\Delta H^o_{combustion} [cyclopropane, g]$.
$...... \, kJ/mol$

How much heat in $kJ$ is produced by the combustion of $15.5 \, g$ of propane? ${C_3H_8} + 5{O_2} \to 3{CO_2} + 4{H_2O}; \Delta{H^o} = -2219 \, kJ/mol$