2. Energy Chemical Change and the Rearrangement of Atoms

3. Energy Defined EEnergy is the ability to do work.

4. Energy can be Transferred  From the potential energy of a dam holding H 2 O back  To the kinetic energy of the H 2 O being released and turning turbines  To the electrical energy produced by the turbines

5. The Law of Conservation of Energy  The law of conservation of energy states that in any chemical reaction or physical process, energy can be converted from one form to another, but it is neither created or destroyed.  This is known as the first law of thermodynamics.

6. Temperature & Energy  Kinetic energy, energy of motion, is directly related to the random motion of atoms and molecules.  Thermal energy, temperature, is a measure of this motion.

7. Chemical Potential Energy  The potential energy of a substance depends upon:  The type of atoms in the substance  The number and types of chemical bonds joining the atoms  The arrangement of the atoms

8. Chemical Potential Energy The energy stored in a substance because of its composition, is called chemical potential energy.

9. The Rearrangement of Atoms  How does the rearrangement of atoms take place? It occurs through the collisions of particles.

10. Increasing Thermal Energy  Slower, low-energy collisions are not effective in producing the rearrangement of atoms. We must increase the thermal energy (E th ) by heating the system.

11. Thermal Energy Increases Kinetic Energy  Adding thermal energy to the system increases the kinetic energy.  The speed of the particles increase.  The temperature of the system also increases.

12. E ch From the E th Account  The energy required to move to a state of higher chemical potential energy must come from the thermal energy of the particles involved in the reaction. An increase in E ch, must be accompanied by a decrease in E th.

13. Energy Transfer  Energy transferred into our system, via heating, always goes into the thermal energy account (E th ). Energy can then transfer from the thermal account to the chemical potential energy account (E ch ).

14. Energy and Decomposition  Consider the decomposition of sodium hydrogen carbonate (NaHCO 3 ) represented below. energy + 2NaHCO 3 (s)  Na 2 O (s) + 2CO 2 (g) + H 2 O (g)

15. A 2-step LOLOL Energy Bar Chart