Understanding Hess' Law and Enthalpy Changes

Hess' Law

Overall enthalpy change is route-independent.

Enthalpy Change

Difference in energy between reactants and products.

Enthalpy of Formation

Energy change when forming one mole of compound.

Combustion

Reaction of substance with oxygen producing heat.

Enthalpy Change of Combustion

Energy released during combustion per mole.

Activation Energy

Minimum energy required for a reaction to occur.

Enthalpy of Reaction

Total heat change during a chemical reaction.

Combustion Products

Substances formed from the combustion process.

Enthalpy Change of Formation of Propane

Energy change for forming propane from elements.

Enthalpy Calculation

Using known enthalpies to find unknown values.

Experimental Measurement Limitations

Challenges in directly measuring certain enthalpy changes.

Rate of Reaction

Speed at which reactants convert to products.

Enthalpy of Reactants

Total energy content of reactants before reaction.