1. Section 10.4 Using Energy in the Real World 1.To understand how the quality of energy changes as it is used 2.To consider the energy resources of our world 3.To understand energy as a driving force for natural processes Objectives

2. Section 10.4 Using Energy in the Real World When we use energy to do work we degrade its usefulness. A. Quality Versus Quantity of Energy

3. Section 10.4 Using Energy in the Real World Petroleum as energy A. Quality Versus Quantity of Energy

4. Section 10.4 Using Energy in the Real World Fossil fuel – carbon based molecules from decomposing plants and animals –Energy source for United States B. Energy and Our World

5. Section 10.4 Using Energy in the Real World B. Energy and our World Electricity Production in the US (2006)

6. Section 10.4 Using Energy in the Real World Petroleum – thick liquids composed of mainly hydrocarbons B. Energy and Our World –Hydrocarbon – compound composed of C and H

7. Section 10.4 Using Energy in the Real World B. Energy and Our World

8. Section 10.4 Using Energy in the Real World Natural gas – gas composed of hydrocarbons, mainly methane (CH 4 ) B. Energy and Our World

9. Section 10.4 Using Energy in the Real World Coal – formed from the remains of plants under high pressure and heat over time; solid composed mainly of Carbon B. Energy and Our World

10. Section 10.4 Using Energy in the Real World B. Energy and Our World Burning Fossil Fuels: Coal: C + O 2  CO 2 Natural Gas: CH 4 + O 2  CO 2 + H 2 O Gasoline (Petroleum) : C 8 H 18 + O 2  CO 2 + H 2 O

11. Section 10.4 Using Energy in the Real World Effects of carbon dioxide on climate B. Energy and Our World Greenhouse effect

12. Section 10.4 Using Energy in the Real World alternative energy sources B. Energy and Our World –Solar –Nuclear –Biomass –Wind –Geothermal –Tidal

13. Section 10.4 Using Energy in the Real World Effects of carbon dioxide on climate B. Energy and Our World Atmospheric CO 2 –Controlled by water cycle –Could increase temperature by 10 o C

14. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Natural processes occur in the direction that leads to an increase in the disorder of the universe. Example: –Consider a gas trapped as shown

15. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force What happens when the valve is opened?

16. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Two driving forces –Energy spread –Matter spread

17. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Energy spread –In a given process concentrated energy is dispersed widely. –This happens in every exothermic process.

18. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Matter spread –Molecules of a substance spread out to occupy a larger volume. –Processes are favored if they involve energy and matter spread.

19. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Entropy, S – function which keeps track of the tendency for the components of the universe to become disordered

20. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force What happens to the disorder in the universe as energy and matter spread?

21. Section 10.4 Using Energy in the Real World C. Energy as a Driving Force Second law of thermodynamics –The entropy of the universe is always increasing.