Unit 3 – Sections B, C & D

1. Unit 3 – Sections B, C & D Petroleum: An Energy Source, A Building Material Source & Energy Alternative to Petroleum

2. HW 1 Read and take notes on B.1 & B.2 (starting on pg. 238)

3. B.1 Energy and Fossil Fuels Fossils fuels originated from organic compounds plants & animals. These organisms originally captured energy from the sun via photosynthesis. Fossil fuels - crude oil, natural gas and coal are buried potential energy.

4. B.1 Energy and Fossil Fuels(continued) Potential energy is the energy of position (or condition). Energy related to motion is kinetic energy.

5. B.1 Energy and Fossil Fuels(continued) In a similar manner, chemical energy is a form of potential energy, is stored within chemical bonds in chemical compounds All of the above are examples of chemical energy !

6. B.1 Energy and Fossil Fuels(continued) CH4 + 2 O2 CO2 + 2 H2O + energy The above reaction produces considerable thermal energy (heat).

7. B.1 Energy and Fossil Fuels(continued) Think of the above as a two step process. CH4 + 2 O2 CO2 + 2 H2O + energy Step 1 CH4 + 2 O2 C + 4H + 4O All bond-breaking steps are energy requiring processes called endothermic changes.

8. B.1 Energy and Fossil Fuels(continued) Step 1 CH4 + 2 O2 C + 4H + 4O In an endothermicchange energy must be added to “pull apart” the atoms in each molecule.

9. B.1 Energy and Fossil Fuels(continued) Step 2C + 4 H + 4 O  CO2 + 2 H2O + ENERGY The formation of chemical bonds is an energy-releasing process called an exothermic changes, because energy is given off.

10. B.1 Energy and Fossil Fuels(continued) Step 1CH4 + 2 O2 + energy C + 4 H + 4 O Bottom line: MORE energy is given off in step 2 than is taken in for step 1. Step 2C + 4 H + 4 O  CO2 + 2 H2O + ENERGY The overall change is exothermic.

11. B.1 Energy and Fossil Fuels(continued) If MORE energy has to be added than is given off the reaction is endothermic.

12. B.1 Energy and Fossil Fuels(continued) In general, if a process converts potential energy into kinetic energy ... then the reverse process ...converts kinetic energy back into potential energy.

13. B.1 Energy and Fossil Fuels(continued) Likewise, if a chemical reaction is exothermic (releases heat)...then the reverse process ...is endothermic (converts thermal energy into potential energy.)

14. B.2 Energy Conversion Energy can change form from chemical to thermal to mechanical to electrical. The law of conservation of energy states that energy is neither created nor destroyed in any mechanical, physical or chemical process.

15. B.2 Energy Conversion(continued)

16. HW 2 Notes from B.4

17. B.4 Energy Efficiency As you car owners have no doubt noticed gasoline (petroleum products) are expensive. And still going up – average cost of 1 gallon of regular (3/26/12) = $3.918

18. B.4 Energy Efficiency(continued) Unfortunately devices which convert chemical energy thermal  mechanical energy are typically less than 50% efficient

19. B.4 Energy Efficiency(continued) Typical automobile in using 100 units of energy will: • Lose : • 33 units through exhaust • 3 units to piston friction • 6 units pumping combustion air • 4 units other engine friction • 29 units cylinder cooling • Use : • 25 units for horsepower

20. HW Before Class Work 2 Answer questions in B.5 1-4 on pg 245, making certain to show all work AND ESPECIALLY CONVERSION FACTORS

21. B.5 Example (How problems should be set up!) = X ANSWER: = X ANSWER: Assume my automobile averages 28.45 miles per gallon and travels 15,000. miles per year. How much fuel will be burned in one year? If gasoline is $3.87 per gallon what will I spent in one year?

22. B.5 Energy Conversion Efficiency 1. Assume an automobile averages 23.0 miles per gallon and travels 11,000 miles per year. • How much fuel will be burned in one year? • If gasoline is $3.00 per gallon what would be spent in one year? 1 gallon 23.0 miles 478 gallons 1 year 11,000 miles 1 year = X ANSWER: 478 gallons/yr $3.00 1 gallon $1434 1 year 478 gallons 1 year = X ANSWER: $1434/yr

23. B.5 Energy Conversion Efficiency(continued) 2. Hybrid-automobile averages 50.0 miles per gallon and travels 11,000 miles per year. • How much fuel will be burned in one year? • If gasoline is $3.00 per gallon what would be spent in one year? 1 gallon 50.0 miles 220 gallons 1 year 11,000 miles 1 year = X ANSWER: 220 gallons/yr $3.00 1 gallon $660 1 year 220 gallons 1 year = X ANSWER: $660/yr

24. B.5 Energy Conversion Efficiency(continued) 3. Q1 automobile uses only 25% of the gasoline’s energy. • How much fuel is wasted each year due to inefficiency? • At $3.00 per gallon , how much $? 359 gallons 1 year 478 gallons 1 year 0.75 = X ANSWER: 359 gallons/yr WASTED $3.00 1 gallon $1077 1 year 359 gallons 1 year = X ANSWER: $1077/yr WASTED

25. B.5 Energy Conversion Efficiency(continued) 4. New car gets 70.0 mile /gallon with a 40% efficient engine. • How much fuel is saved per year versus car 1 and 2? • How much fuel & $ is wasted? 1 gallon 70 miles 157 miles 1 year 11,000 miles 1 year = X ANSWER: Car 1 478 gallon/yr – 157 gallon/yr = 321 g/yr Car 2 220 gallon/yr – 157 gallon/yr = 63 g/yr 94 gallons 1 year 157 gallons 1 year 0.60 = X ANSWER: 359 gallons/yr X $3.00 gallon = $283 WASTED

26. 5 point Quiz (Remember how problems should be set up!) = X ANSWER: = X ANSWER: Assume my new hybrid automobile averages 51 miles per gallon and travels 14,500. miles per year. How much fuel will be burned in one year? If gasoline is $3.96 per gallon what will I spent in one year?

27. B.6 Combustion Pre-read B.6 – pg 248-251

28. B.6 Combustion(continued) Questions ? Characteristic property of material is the amount of heat it takes to raise the temperature of 1 g of material 1°C This is called the specific heat capacity of the material.

29. HW Read and take notes on B.7 starting on pg. 251

30. B.7 Using Heats of Combustion With enough O2 and complete combustion the burning of a hydrocarbon is expressed as follows: Hydrocarbon + oxygen gas  carbon dioxide + water + thermal energy Thermal energy is a product because it is produced by the reaction. Ethane C2H6

31. B.7 Using Heats of Combustion(continued) To complete this equation, the CORRECT quantity of thermal energy involved must be included 2 C2H6 + 7 O2 4 CO2 + 6 H20 + ?thermal energy Per the table 3.6 on page 250 ethane releases 1560 kj/Mol 2 C2H6 + 7 O2 4 CO2 + 6 H20 + 3120 kj

32. B.7 Using Heats of Combustion(continued) Sample: How much thermal energy would be produced by burning 12.0 g octane, C8H18? 47.8 kj 1 g octane 574 kj 12.0 g octane = X

33. Classwork Class work B.8 on pg 252 – Questions 1 a.-d.,2 a. & 3 a.-d. - show work and especially conversion factors

34. B.8 Heats of Combustion 1. Write chemical equations including thermal energy for : • propane • Butane • octane C3H8 + 5 O2  3 CO2 + 4 H20 + 2200 kj 2 C4H10 + 13 O2  8 CO2 + 10 H20 + 5718 kj 2 C8H18 + 25 O2  16 CO2 + 18 H20 + 10900 kj

35. B.8 Heats of Combustion(continued) 1. Write chemical equations including thermal energy for : (continued) • decane 2 C10H22 + 31 O2  20 CO2 + 22 H20 + 13540 kj

36. B.8 Heats of Combustion(continued) 2. a. How much thermal energy is produced burning 2 Mol of octane? 5450 kj 1 Mol octane = 10,900 kj 2 Mol octane X ANSWER: 10,900 kj produced

37. B.8 Heats of Combustion(continued) • Write a chemical equation for burning coal including the thermal energy. 3. C (s) + O2  CO2 + 394 kj

38. B.8 Heats of Combustion(continued) • Gram for gram which is the better fuel carbon or octane? Explain your answer using calculations. 3. Octane releases 47.8 kJ/g (Table 3.6 on pg 250) Burning coal releases 1 Mol C 12.01 g C 394 kj 1 Mol C 32.8 kj/Mol = X Octane is better on a mass basis.

39. B.8 Heats of Combustion(continued) 2. b. How much thermal energy is produced burning 1 gallon of octane? 5450 kj 1 Mol octane = 10,900 kj 2 Mol octane X ANSWER: 10,900 kj produced

40. Quiz Tomorrow on Section B Please be prepared

41. HW on C.1 Notes on C.1 Creating New Options: Petrochemicals pg 262

42. C.1 Creating New Options: Petrochemicals Until early 1800s everything we used was made of Wood Stone Metals

43. C.1 Creating New Options: Petrochemicals(continued) All medicines and food additives came from natural sources.

44. C.1 Creating New Options: Petrochemicals(continued) At that time celluloid (wood) and shellac (animal material) were the only source for commercially produced polymers.

45. C.1 Creating New Options: Petrochemicals(continued) Polymers are typically large molecules, 500 to 20,000 repeating units. The single unit is known as a monomer.

46. C.1 Creating New Options: Petrochemicals(continued) Many of today’s polymers are created using compounds produced using oil or natural gas and they are called petrochemicals.

47. C.1 Creating New Options: Petrochemicals(continued) Most petrochemicals serve as raw materials producing a wide range of polymers.

48. C.1 Creating New Options: Petrochemicals(continued) Synthetic polymers include: • Paint components • Fabrics • Rubber • Insulating materials • Foams • Adhesives • Molding • Structural materials

49. C.1 Creating New Options: Petrochemicals(continued) It takes few builder molecules to make many new substances. Ethene C2H4 is an example of a simple builder molecule. The arrangement of electrons is called a double covalent bond – the carbons are sharing two pair of electrons.

50. C.1 Creating New Options: Petrochemicals(continued) As the double bonds have a high reactivity they are easily transformed. Acid catalyst Ethene water Ethenol The water molecule “adds” to the double-bonded carbons – this type of reaction is called an addition reaction.