The total enthalpy change in a chemical reaction is equal to the algebraic sum of the enthalpy changes of the individual steps of the reaction. This statement is associated with which scientist?

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

The heat of combustion of methane is $-809 \, kJ \, mol^{-1}$. What is the calorific value of methane in $kJ \, g^{-1}$?

Calculate the enthalpy change for the reaction $H_{2(g)} + Br_{2(g)} \rightarrow 2HBr_{(g)}$ in $kJ$. The bond energies of $H-H$,$Br-Br$,and $H-Br$ are $435$,$192$,and $364 \, kJ \, mol^{-1}$ respectively.

When $2 \, mol$ of $C_2H_6$ is completely combusted,$3129 \, kJ$ of heat is released. The heat of formation of $C_2H_6$ is ..... $kJ/mol$. Given that $\Delta H_f$ for $CO_2$ and $H_2O$ are $-395 \, kJ/mol$ and $-286 \, kJ/mol$ respectively.

Which of the following substances has the highest value of standard molar enthalpy of formation at $298 \ K$?