Heats of Reaction and Hess's Law experiment tells you to look up three values. Write down these values. Be sure to clearly indicate which value you are typing. Be sure to include units and to use joule based units (i. e. joules/mol or kJoules/mole).

Enthalpy of reaction (kJoules/mole)

Heat of formation of products (kJoules/mole)

Heat of reaction of reactants (kJoules/mole)

Explanation:

The general expression for calculating the overall enthalpy of reaction is given as following:

ΔH = ∑ΔH[producst] - ∑Δ[reactants]

Thus, the heat of reaction is given as the difference between the formation of the products and the formation of the reactants. The units are expressed as kJ/mol of reactants or products.

Thus, the three values are fundamental in the determination of the overall energy of the reaction from Hess' Law.