3 SBS 1-10 p.258

1. Petroleum is sometimes considered "buried sunshine" because the energy released by burning these fuels represents energy originally captured from sunlight by prehistoric green plants during photosynthesis.

2. a. potential energy: energy of position (wind-up toy race car)

    b. kinetic energy: energy related to motion (movement of car)

3. When an energy-releasing chemical reaction takes place, bonds break and reactant atoms reorganize to form new bonds.

4.  A molecule of butane has more potential energy.

5. a. potential energy

    b. potential energy

    c. kinetic energy

    d. potential energy

    e. kinetic energy

6. Energy is required to break chemical bonds because in an endothermic change, energy must be added to "pull apart" the atoms in each molecule. Thus energy appears as a reactant.

7. a. exothermic: energy is released

    b. endothermic: energy is added to pull apart the atoms

    c. exothermic: energy is released

8. Burning a candle is an exothermic reaction because the quantity of energy stored in the reactants is less than the quantity of energy stored in the products; more energy is given off than added.

9. 

10. The law of conservation of energy states that energy can change from but cannot be created or destroyed in any chemical reaction or physical change.