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The activation energy (for any reaction) is the difference between the reactant enthalpy and the high point on the reaction pathway. Activation energy is always positive, as the energy is taken in by the reactants.
The enthalpy change is calculated from the difference in enthalpy between the enthalpy of the products (Hp) and the reactants (Hr). ΔH = Hp – HrThe calculation is product minus reaction, which means that enthalpy changes can be positive or negative. |
