This video is about Thermochemistry and explains in details Hess’s Law, Standard Enthalpy of Formation and Heating and Cooling Curve. In this video also you will learn about the use of hess’s law to calculate the enthalpy change of an overall reaction which is the sum of several steps. Moreover, you will learn how to calculate the enthalpy change from the standard enthalpy of formation of the reactants and products. After watching this video, you should be able to:

**Hess’s law**

- Write and explain thermochemical equations.
- Know the two rules for manipulating (reversing and multiplying) thermochemical equations.
- Applying Stoichiometry to Heats of Reaction.
- State Hess’s law of heat summation.
- Use Hess’s law to calculate the enthalpy change for one reaction from the enthalpy changes of a number of other reactions.

**Standard Enthalpies of Formation**

- Define standard state.
- Define standard enthalpy of formation.
- Calculate energy changes associated with chemical reactions using Hess’s law, standard enthalpies of formation, or calorimetry.