Unit 4 B.3 (p.344) #1-4
1. Human exposure to ultraviolet radiation is potentially more harmful than exposure to infrared radiation because too much exposure to ultraviolet radiation can cause a sunburn, which can lead to skin cancer.
2. Two essential roles played by visible solar radiation is one they can energize electrons in some chemical bonds, which, two, provides energy needed for photosynthesis reactions.
3. Dry, arid regions in the United States experience wider air-temperature fluctuations from night to day then do more humid states because there is less water vapor; therefore infrared radiation isn't stored, reradiated, or reflected back into the atmosphere from electromagnetic radiation that is transformed in the clouds to produce infrared radiation. However, heat does reach the earth.
4. a. Day time temperatures would be affected if Earth had less dense atmosphere because it would be colder. This is because with less greenhouse gasses, like CO2 or H2O, less infrared radiation would be absorbed and be reflected back onto the atmosphere from the UV and visible radiation that was transformed to IR radiation in the clouds. In all less heat energy would be formed from less absorbed infrared radiation.
b. The night time temperatures would be affected if Earth has less dense atmosphere because it would be colder than it would normally be because one there is no presence of the sun and two because less infrared radiation is absorbed and reflected back onto Earth, making it colder.
Unit 4 B.8 (p.350) #1-6
1. 1kg of carbon dioxide is produced daily by all 10 Riverwood High School buses.
2. 0.40 L of fuel are consumed daily by buses idling at Riverwood High School.
3. In a 180-day school year, 180g of carbon dioxide would be released into the atmosphere by these buses, and 72L of fuel would be consumed.
4. Atmospheric CO2 levels have increased by about 30% since 1800 because of the clearing of forests, combustion of cutting and scrap timbers, and because of the burning of fossil fuels.
5. Yes, I do think the school bus idling policy will significantly affect annual worldwide supply of fossil fuels that are converted to carbon dioxide because as years go by, more fossil fuels will be needed for more buses.
6. The school buss idling policy is necessary to help preserve the burning of fossil fuels. And hopefully with this policy it will help when years go by and more fossil fuels will be needed.
Unit 3 SAS (p.233) #1-30 (except: 2,4,9,14,24,25)
1. Hydrocarbons are molecular compounds that only contain atoms of hydrogen and carbon.
3. The characteristic of petroleum that make it a valuable resource is that it is used as fuel in many U.S. automobiles, petroleum-based fuels provide heat to homes, generates electricity, and is useful to produce everyday products.
5. By saying oil is crude what is meant is that it is pumped from under grown and cannot be commercially used in its natural state, it must go through refinement where it is separated into simpler mixtures.
6. a. The average number of barrels of petroleum used daily int he United States for building purposes is: 0.11 x 20,000,000 = 2,200,000 barrels
b. The amount of barrels of petroleum burned as fuel daily in the United States is:
0.89 x 20,000,000 = 17,800,000 barrels
7. Fuels obtained from crude petroleum include heating and cooking fuel, petrol jelly, asphalt, petroleum coke, and many oils refined oils, gas oil, road oils, and more.
8. a. Four household items made from petroleum: clothing, carpeting, sports equipment, and plastic bottles.
b. Clothing could be made out of cotton, carpeting could also be made out of cotton, sports equipment can be made out of rubber like rubber balls, and plastic bottles could be made out of aluminum.
10. a. The world region that has the most petroleum reserves relative to its population is Eastern Europe.
b. The region that has the least petroleum reserves relative to its population is Central Asia.
11. a. The regions that consume a greater proportion of the world's supply of petroleum than they possess are North America, Central Asia, Far East, and Oceania, Western and Eastern Europe.
b. The regions that consume a smaller proportion of the world's supply of petroleum than they posses are Middle East, Africa, Central and South America.
12. Density could be used to separate two different liquids under the conditions that a substance is insoluble in each other.
13. A mixture of water and acetone would be the easiest to separate from each other since water has the highest boiling point and acetone has the lowest boiling point of the four substances listed; therefore, they would separate easily by distillation.
15.
16. Fractional distillation does not separate each substance in crude oil, instead it produces many different mixtures called fractions. Fractional distillation is a continuous process that consists of a distillation column and various temperatures in order to separate solutions. Simple distillation only involves a apparatus and separates a solution using evaporation and condensation.
17. Three useful products that derived from petroleum's fractions:
- light: motor gasoline and refined oil
-intermediate: gas oil and heavy furnace oil
-heavy: lubricating oil/grease and heavy oils/wax
18. In a distillation tower, I would expect the fraction with the highest boiling point to be removed at the bottom of the tower because it is hotter at the bottom, which is needed to separate the bonds between molecules. And there are thick liquids that never vaporize
19. After fractional distillation, a way to further separate the mixtures is distillation.
20. In the order from highest to lowest according to their boiling points are methane, pentane, hexane, octane. The higher the boiling point is, the stronger the intermolecular forces.
21. A covalent bond is the sharing of two or more valence electrons between two atoms, allowing both atoms to completely fill out their outer shells.
22. Atoms with filled outer electron shells do not form covalent bonds because they are usually stable; therefore, they are chemically unreactive.
23. The analogy that two dogs are tugging on the same sock describe the way that shared electrons hold together atoms in a covalent bond because the two dogs pulling away from each other are still connected by the need to want the sock; therefore, sharing the sock that connects them together.
26. a. The information that a structural formula conveys but a molecular formula does not is the make up of a molecule, as well as how high the boiling point is.
b. A structural formula is an inadequate representation of an actual molecule because it shows how strong molecular bonds within the formula is, as well as the boiling point of the formula
27. a. Lewis dot structure
b. Structural formula
28. The electron dot representation of carbon atom only shows four dots and not six because two electrons are located in the inner shell of an atom, and the four electrons are located in the outer shell.
29. a. C9H20
b. C16H34
c. C10H22
d. C18H38
30. a. 128g
b. 226g
c. 142g
d. 254g
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