Wednesday, July 24, 2013

Homework #10

1. Because infrared radiation is mostly heat energy, exposure to it is not as harmful as exposure to ultraviolet light, which is the most energetic form of sun radiation. Ultraviolet light can cause sunburns and skin cancer and can even sterilize materials by killing bacteria and destroying viruses (UV-C radiation).


2. Visible solar radiation provides the energy needed for photosynthesis and the visible scattering of light during sunset. 


3. Since there is less water vapor, and therefore, less greenhouse gas caused by water vapor in dry and arid regions such as New Mexico and Arizona, infrared radiation is not as stored and reradiated and reflected back into the atmosphere from the entering of UV and visible light that is transformed into IR radiation in clouds, but the visible and UV radiation directly exposed to the surface of the earth  is used to heat earth. This results in wider air-temperature fluctuations from night to day than states with more humid conditions, for not as much heat is stored in the clouds.


4. 

a. The daytime temperatures would be much cooler, because with less greenhouse gases, less infrared radiation would be stored and reradiated and reflected back into the atmosphere from the transformation of UV and visible radiation to IR radiation in clouds. Less stored heat energy would enter throughout the day.
b. Without stored heat energy in the atmosphere, nights would be very cold without the presence of the sun.

pg. 350


1. The mass of carbon dioxide produced daily by all 10 Riverwood High School buses is 1 kg.

2. 0.40 L of fuel are consumed daily by buses idling at Riverwood High School.

3. In a 180-day school year, 180 kg of carbon dioxide would be released into the atmosphere by these buses while idling. 72 L of fuel would be consumed.

4. Atmospheric CO2 levels have increased by about 30% since 1800 due to clearing forests, combustion of cuttings and scrap timber, and the burning of fossil fuels.

5. No, because enough fossil fuel gas is produced naturally on its own.

6. The school bus-idling policy may seem necessary to some people in order to preserve the atmosphere and prevent pollution.


pg. 233


1. A hydrocarbon is a molecular compound that only contains atoms of hydrogen and carbon.

2. Petroleum is not only a nonrenewable resource, but a very versatile material that is used both as fuel that can be converted to gasoline; therefore, it can be used as heat sources, can deliver energy to generate electricity, can generate energy, and is also used to produce useful every day products, it is a valuable resource.


3. Oil is crude because it is pumped from underground and using it in a natural state without some degree of refinement where it is separated into simpler mixtures is not possible (through fractional distillation).


6.
a. 2,200,000 barrels
b. 17,800,000 barrels


7. Heating and cooking fuel, petrochemicals, kerosene, diesel fuel oil, lubricating oil and grease, heavy oils and wax, petroleum jelly, road oils and asphalt, petroleum coke.


8.
a. Water bottle, sports equipment, clothing, artificial limbs.
b. A water bottle can be made out of aluminum, bamboo can be used to make light, flexible, and durable sports equipment, clothing can be made of cotton, and artificial limbs can be made of iron (although it is much better to make them out of plastic).


10.
a. The Middle East has the most petroleum reserves relative to its population.
b. Central Asia, Far East, and Oceania have the least petroleum reserves relative to its population.


11.
a. North America, Central Asia, Far East, and Oceania, Western Europe, and Eastern Europe consume a greater proportion of the world’s supply of petroleum than they possess.
b. The Middle East, Africa, and Central and South America consume a smaller proportion of the world’s supply of petroleum than they possess.


12. Density can be used to separate two different liquids if the substances are insoluble with each other.


13. Water and acetone would be the easiest to separate from each other by distillation. This is because since water has the highest boiling point, and acetone has the lowest of the four substances, water and acetone would separate fairly quickly and easily by distillation.

15)  


16. Fractional distillation does not separate each compound in crude oil, but produces several distinctive mixtures, called fractions. Fractional distillation is also a continuous process. The crude oil is heated in a furnace and then pumped into the fractionating tower. The temperature within the tower (distilling column) is highest at the bottom and decreases towards the top. Smaller and lighter molecules that have lower boiling points vaporize to the top of the tower, and fractions with larger molecules with higher boiling points condense back to liquid in trays in the lower part of the column. Substances with the highest boiling points never vaporize, but drain from the base—bottoms.

17. 
Light: Aviation gasoline and motor gasoline, kerosene, and refined oils.
Intermediate: Gas oil, petrochemicals, heavy furnace oil, and diesel fuel oil.
Heavy: Lubricating oil and grease, heavy oils and wax, and cracking stock.


18. The fraction with the highest boiling point range would be removed at the bottom. This is because they are thick (viscous) liquids that never vaporize, called bottoms; they drain from the tower’s base.


19. A way to further separate the components of each fraction would be through distillation after a fractional distillation.


20. Methane (CH4), pentane (C5H12), hexane (C6H14), octane (C8H18).
The boiling points increase with greater amounts carbon atoms within the straight-chains of hydrocarbons; the higher the boiling point, the stronger the intermolecular forces are between the molecules.

21. A covalent bond is the sharing of two or more valence electrons between two atoms, allowing both atoms to fill their outer shells completely.

22. Atoms with filled electrons (8 valence electrons) are particularly stable, and therefore, tend to be chemically uncreative. Noble gases are atoms with filled outer electron shells.


23. Since the two dogs desire the sock, they must share it, although they desire to have it for themselves; like repelling electrons, the dogs pull away from each other, but are still connected by the bond they share with the sock connecting them.

26.
a. A structural formula shows the makeup of a molecule, as well as how high the boiling point is, where as a molecular formula just shows the amount of atoms each element in the formula possesses.
b. The structure of a formula shows how strong molecular bonds within the formula is, as well as the boiling point of the formula.

27. See drawings


28. The electron-dot representation of a carbon atom only shows four dots because the four dots represent the valence electrons, located on the outer (and not inner) shell of the atom, where two electrons are located.

29.
a. C9H20
b. C16H34
c. C10H22
d. C18H38

30.
a. 128g
b. 226g
c. 142g

d. 254g

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