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Petroleum: To build or To Burn. Part B: Petroleum as a Source of Energy. Introduction. 1. How is Petro thought to be formed? plants and animals died and eventually covered with sediments pressure, heat, and microbes converted the living matter into petroleum trapped in porous rocks.
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Petroleum: To build or To Burn Part B: Petroleum as a Source of Energy
Introduction 1. How is Petro thought to be formed? • plants and animals died and eventually covered with sediments • pressure, heat, and microbes converted the living matter into petroleum trapped in porous rocks
2. Describe the history of the use of Petro? • began to be used 5000 years ago • ancient Middle Easterners collected the petro that seeped from the ground and used it to waterproof ships and canals, and the pave roads • 1000 AD, Arabs had developed a way of processing oil to make kerosene for lighting, at the same time the Chinese were extracting oil from wells that were half mile deep, Marco Polo described these • First oil well in the US was in PA in 1859
Energy: Past, Present, and Future 3. What is our main source of energy? • the sun 4. How is this energy stored? • as chemical energy in plants 5. How is the energy transferred? • animals eat these plants storing the energy in biomolecules
6. Name some examples of stored energy? • wood, water, wind, and animal power 7. What used to be our main source of stored energy? • wood
Use Figure III.10 to answer the following questions 8. Since 1850, has our overall use of energy remained constant, increased at a fixed rate, or accelerated? Describe at least two factors that might explain he trend. 9. Did overall energy use decrease at any time over the past 130 years? If so, when did this occur? Why? 10. Over what time period did wood supply more than 50% of our overall energy needs? What was the chief form of long distance transportation during this period?
11. What factors might explain the declining use of wood after this period? What energy was the next to rise in importance? 12. Compared to other energy sources, only a small quantity of petro was used prior to 1910. What do you think was petro’s main use at that time? 13. Oil became increasingly important about the same time that the use of coal reached its peak. When did this occur? What can explain the growing use of petro after this date?
14. What is the most recent energy source to enter the picture? What is the major use of this energy source? 15. What has played a large role in the development of history in our country? Do Chemquandary 1 on page 195
Energy and Fossil Fuels 16. What are fossil fuels? • petroleum, natural gas, and coal 17. Where do fossil fuels originate from? • biomolecules of prehistoric animal and plant life
18. What is one way of thinking of the concept of energy being released from fossil fuels? • energy stored in loaded mousetrap, energy must be put in to set it, then when it is triggered, energy is released 19. How is chemical energy released? • during the breaking or forming of bonds during a chemical reaction
20. Give an equation that demonstrates this release. • 2H2 + O2 --> 2HOH + energy 21. What do we call the release of energy in a reaction? • exothermic reaction
22. What do we call the addition of energy to make the reaction get started? • activation energy 23. What analogy can be used to explain an exothermic reaction? • kicking a stone on top of a hill and having it fall down
24. What kind of reaction is one that takes in energy? • endothermic 25. What analogy can be used to explain an Endothermic reaction? • having to roll a big boulder up a hill
26. Draw Energy Diagrams to demonstration both endo and exo reactions 27. What are energy conversions? • converting of one form of energy into another
28. What are some different types of energy? • chemical, electrical, electromagnetic(light), heat, sound, mechanical, electrostatic, magnetic 29. What are the energy conversions in the following examples? a. drying your hair b. photosynthesis c. gasoline to rear window defrosting in an automobile
30. What are two problems associated with energy conversions? 1. You will lose energy with every interconversion 2. Sometimes pollution is emitted with every interconversion 31. How efficient is a well tuned automobile? What happens to the rest of the energy? about 25% efficient. The rest is lost to the surroundings
32. What would be one way of increasing the energy efficiency in machines? • reduce the number of energy conversions • Read Chem at Work on page 198 for Quiz tomorrow
The Chemistry of Burning 33. What is the overall reaction that is involved in most examples of “burning”? • Hydrocarbon + O2 --> CO2 + H2O 34. Give the equation for the burning of a candle • C25H52 + O2 --> CO2 + H2O + Heat
35. What is heat of combustion? • the amount of energy given off when something is burned 36. What equation is used to determine heat of combustion? • q = m x T x SH where q is the energy given off or absorbed during a reaction, T is the final temperature minus the initial temp and SH is the Specific Heat of the substance being heated
37. What is specific heat? • the amount of energy that a 1 g sample of a substance can absorb before it can go up 1 C
38. Determine whether the following materials would have a high or low specific heat • Oil • Water • Plastic • Wood • Perfume • Alcohol
39. What are the heat of combustions for the common fuels that we use? Fuel name HOC in kJ/mol CH4 methane 55.6 C3H8 propane 50.0 C6H14 hexane 48.2 C7H16 septane 48.2 C8H18 octane 47.8 40. What is the heat of combustion for coal? • 394 kJ/mol
Ex. 1 How much energy is given off when 3.00 g of a candle burns to heat up 50 g of water from 20 C to 30 C? The specific heat of water is 4.18 J/gC. What is its heat of combustion? • Ex. 2 How much energy is given off when 5.00 g of a gasoline burns to heat up 50 g of water from 20 C to 35 C? The specific heat of water is 4.18 J/gC. What is its heat of combustion?
41. What happened to the use of Kerosene after the invention of the electric light bulb? • Drastic decline 42. What did chemist figure out what to do at this time? • Process of convertng larger moelcules in kerosene into smaller, gasoline sized molecules by heating it to 600 to 700C
43. What do we call this process? • Cracking 44. How much of today’s crude oil is cracked? • A third 45. How has the process been improved? • By adding a catalyst
46. What is a catalyst? • A substance that increases the speed of a reaction without affecting it in any other way 47. What is an example of an enzyme that is used by human beings to digest foods? • enzymes
48. Without enzymes, how long would it take for you to digest today’s meal? • Months 49. What is the most common substance produced from cracking? • gasoline
50. What is gasoline composed of? • Chains of carbon, 6 carbon(hexane), 7 carbon(heptane), and 8 carbon(octane) long 51. Draw the dot diagram for octane(C8H18)?
52. What causes engine knocking? • Rapid burning of the fuel 53. How did chemist solve this problem? • By using branched chain molecules
54. What is an isomer? • Same formula different structure 55. Draw an isomer of octane?
56. What is an octane rating? • Describes the quality of the fuel • Isooctane is 100, heptane is 0 • 87% Isooctane, 13% heptane is 87
57. What is a cheap way of increasing octane rating? • Adding tetraethyl lead(C2H5)4Pb to the fuel 58. What did the tetraethyl lead do? • Slowed down the burning of the straight chain hydrocarbons
59. Why has this method been banned? • Lead was discharged into the atmosphere along with the exhaust gases • Lead is very harmful to the environment 60. So what have gasoline makers relied on? • Oxygenated fuels
61. What are oxygenated fuels? • Hydrocarbons that contain oxygen like alcohols 62. What are the advantages to using alcohols? • Makes the fuel burn more efficiently and cleaner • Cheap to make
63. What is a good example of these alcohols? • Methanol 64. What is methanol made from? • Natural gas, corn, coal, wood
65. What other alcohol is used? • Ethanol-drinking alcohol 66. What is a promising new fuel additive? • MTHF, methyltetrahydrofuran, has an octane rating of 87 and the ability to increase the oxgyeng level of the gas. Made from renewable resources that can be found in Paper mill waste
Do Chemquandary 2 on page 211 • Do Making Decisions on Page 212