2. How did fossil fuels form?
 500 million years ago living matter-
mostly plants- died and was buried in
sediment.
 Pressure, heat, and microbes converted
the organic matter into petroleum.
 Buried sunshine?

4. Potential Energy
 Stored energy or energy of position

5. Kinetic Energy
 Energy related to motion
 video clip

6. Chemical energy
 A form of potential energy that is stored
in the bonds of chemical compounds.
 Burning hydrocarbons releases energy
in the form of heat and light

7. Types of energy in chemical
reactions
 Endothermic: energy “enters” the
reaction
 Feels ________________
 Exothermic: energy “exits” the reaction
 Feels ________________

8. Reactions take place in 2 steps:
 1) Bonds must be broken in the starting
reactants.
 * When bonds are broken, energy is
released. So this is an exothermic
process.
 CH4 + 2O2  C + 4H + 4O + Energy

9. Step 2:
 Separated atoms now join to form a new
bonds to make the products.
 It takes energy to form bonds, so this
process is endothermic.
 Energy + C + 4H + 4O  CO2 + 2 H2O

10. CH4 + 2O2  C + 4H + 4O

11. Net equation for burning of
methane
 CH4 + 2O2  CO2 + 2H2O + energy
 Notice the energy shows up as a
product so more energy was released
so the reaction is exothermic.
 gummy bear experiment

12. Energy + 2H2O  2H2 + O2
 Is more energy put into the reaction or
released by the reaction?
 Is the reaction endothermic or
exothermic?
 endothermic reaction