Enter the sum of enthalpy in the products (J) and the sum of enthalpy in the reactants (J) into the Heat of Formation Calculator. The calculator will evaluate the Heat of Formation. 

Heat of Formation Formula

The following two example problems outline the steps and information needed to calculate the Heat of Formation.

HOF = EP – ER 

Variables:

  • HOF is the Heat of Formation (J)
  • EP is the sum of enthalpy in the products (J) 
  • ER is the sum of enthalpy in the reactants (J) 

How to Calculate Heat of Formation?

The following steps outline how to calculate the Heat of Formation.


  1. First, determine the sum of enthalpy in the products (J). 
  2. Next, determine the sum of enthalpy in the reactants (J). 
  3. Next, gather the formula from above = HOF = EP – ER .
  4. Finally, calculate the Heat of Formation.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

sum of enthalpy in the products (J) = 5

sum of enthalpy in the reactants (J) = 3

HOF = EP – ER  = ?