The reaction is exothermic, releasing heat to the surroundings.

The reaction is endothermic, absorbing heat from the surroundings.

The temperature of the substance increases less than a substance with a low heat capacity.

Measure the initial temperature of reactants and calorimeter, conduct the reaction inside the calorimeter, measure the final temperature, and calculate the heat released or absorbed using $q = mc\Delta T$.

Sum of bond energies broken minus the sum of bond energies formed: $\Delta H = \Sigma \text{Bonds Broken} - \Sigma \text{Bonds Formed}$.

Sum of enthalpies of formation of products minus the sum of enthalpies of formation of reactants: $\Delta H = \Sigma \Delta H_f^\circ \text{(Products)} - \Sigma \Delta H_f^\circ \text{(Reactants)}$.

If a reaction can be expressed as a series of steps, the enthalpy change for the overall reaction is the sum of the enthalpy changes for each step. Manipulate individual reactions (reversing or multiplying) to match the target reaction.

Exothermic: $\Delta H < 0$, heat is released. Endothermic: $\Delta H > 0$, heat is absorbed.

Bond Enthalpies: Uses bond breaking and forming energies. Enthalpies of Formation: Uses standard enthalpies of formation of products and reactants.