Energy Stoichiometry

1. Relate energy changes during reactions to amounts of reactants and products mathematically

Energy Stoichiometry

Along with an equation, you will be given enthalpy of reaction (). Note the following:

• A negative enthalpy indicates an exothermic reaction.
• A positive enthalpy indicates an endothermic reaction.
• Enthalpy refers to all products equally.

Example: Given: ; How much energy would be transferred if 0.18 mol of ammonia was produced?

Note

When discussing amount of energy transferred, the sign is irrelevant, so it is positive (in that vien, we cut off the sign on 92.2 kJ, so that it is positive, because whether or not it is endothermic or exothermic doesn’t change how much energy is transferred).