4SBS pg.350 #1-6

1)
.25 kg x 4 x 10
= 10 kg

2) 
.10 L x 4 x 10
= 4 L

3) 
.25 kg x 4 x 10 x 180
= 1,800 kg

4) It is a much quicker  when buses convert the fossil fuels to atmospheric carbon dioxide. Atmospheric CO2  levels have increased by 30% since 1800 the increasing use and development of  transportation has caused an increase in fuel, resulting in a increase of CO2. 

5) I don't think that the bus idling policy will help the worldwide supply of fossil fuels because for every two minutes a car is idling, it uses about the same amount of fuel it takes to go about one mile, so in reality it uses a lot of fuel to idle, however if you actually want to save fossil fuel than the you should just turn of the bus at each stop. 

6) Isiah Martin and others may think that the bus idling policy is necessary because they may think that is helps the envioment and students safety, when in fact idling is linked to increases in asthma, allergies, heart and lung disease and cancer.

 

4BSB pg.350 #1-4

1) Human exposure to ultraviolet radiation is more harmful than exposure to infrared radiation because infrared radiation is basically heat energy, while ultraviolet light  can cause sunburns, and with extensive exposure could lead to skin cancer. 

2)  Two roles played by visible solar radiation is that it can energize electrons in some chemical bonds and it can also scatter throughout Earth and causing red sunsets and blue skies. 

3)  Dry, arid regions experience wider air-temperature fluctuations from night to day than do states with more humid conditions because since there is less water vapor, infrared radiation is not stored, reradiated, and reflected back into the atmosphere from the transformation of UV and visivle radiation to infrared radiation in the clouds, resulting in the lack of heat stored in the clouds. 

4) 

a. The daytime temperatures would be much cooler because less stored heat energy would enter throughout the day.
b. Nights would be cold since there is less heat to store during the day. 

4SBS pg.360-361 #1-8, 14-20

1) The frequency of electromagnetic radiation/photons and energy are directly proportional.

2) The word spectrum a good descriptor of the types of energy found in electromagnetic radiation because the spectrum shows the range of energy from high to low.

3) Visible light is useful in plant photosynthesis while other forms of electromagnetic radiation are not because visible radiation can energize electrons in some chemical bonds-- providing energy needed for photosynthesis reactions. 

4)
a. Infrared, visible, ultraviolet
b. Infrared radiation warms living things. Visible radiation can energize electrons in chemical bonds and  ultraviolet radiation can cause sunburns, skin cancer, and can kill bacteria and destroy viruses. 

5) Ultraviolet light is effective for this use because UV-C can kill bacteria and destroy viruses due to the fact that the photons have enough energy to break covalent bonds. 

6) Carbon dioxide and water molecules, absorb infrared radiation and reradiate the energy back to earth. Visible radiation causes red sunsets and blue skies, due to the scattering of a protion of the sun's radiation by water, air, and dust. UV-C radiation is absorbed in the stratosphere before reaching earth's surface and UV-A and UV-B radiation is absorbed by the stratospheric ozone layer

7) Two main effects of the solar radiation that reaches Earth's surface is when more greenhouse gases are produced, which results in more energy reradiated on earth's surface and  hotter water affecting the hydrologic cycle.

8) 

a.  Asphalt warms up more quickly than lakewater when exposed to sunlight. 

b. Water absorbs infrared light and can reradiate it back to earth's surface, while asphalt directly reflects light sources back into space.

14) CO2 and water vapor are both greenhouse gases, that absorb infrared radiation that is readiated from Earth's surface, holding warmth in the atmosphere, thus maintaining moderate temperatures at earth's surface. 

15) 

a. 

Natural: 1. burning natural gas 2. burning coal 
Human: 1. breathing 2. clearing forests b.
Natural: 1. decomposition of plants 2. decomposition of animal wastes
Human: 1. fossil fuels 2. livestock

16)

a. increase in greenhouse/atmospheric gases, higher air pressure.
b. decrease in greenhouse/atmospheric gases, lower air pressure.

17) On a sunny winter day, a greenhouse with transparent glass walls is much warmer than is a structure with opaque wooden walls because infrared light cannot escape through the glass. 

18) 

a. 

b.

19) Three chemical reservoirs of carbon atoms include atmospheric CO2 gas, solid calcium carbonate, and natural gas.

20) A carbon atom could be part of the atmosphere as a gas, a part of the lithosphere as a plant or animal waste decay and lastly as part of the hydrosphere as limestone.

It's no myth, just call us Lith: Retrieving Copper Lab

Makena G.

Nina G. 

Nicolette E.

Dr. Forman 

Chemistry

Questions: 

1)

a. Since CuO does not react with HCl, but copper does, by adding 50 mL HCl to our beaker of 0.99 g of what we thought was pure CuO, we were able to see unconverted Cu form at the bottom of the beaker. This means that our original reaction was incomplete.

b. Maybe by exposing more of the original copper to oxygen, a more complete reaction would have occurred and more copper(II) oxide would have formed.

2)

a. Only .71 g reacted when we heated it. 

b. 0.71/0.99 x 100% = 71%

71% of the total copper sample reacted when heated.

3)

a. Zn: + Cu2+ → Zn2+ + Cu:

b.                                                                      

i. Zn was oxidized.

ii. Cu was reduced.

iii. Zn is the reducing agent.

iv. Cu is the oxidizing agent.

4)

a. The color of the solution cleared and the zinc became brick red and broke apart.  

b. This is because since zinc is more reactive than copper, the zinc caused copper to reduce as it oxidized in the solution.

c. Once the color was completely clear, it was an indication that the Cu^2+ ions in the solution had reduced into solid Cu. The zinc had oxidized and became Zn2+ ions in the solution.

5)

a. Cu2+ ions and solid Zn were “used up” in this recovery process.

b. Cu2+ reduced into solid Cu and Zn was oxidized into Zn2+ ions within the solution.

Heating the copperoxide with hydrochloric acid

Zinc reacting with copper

Data Table: 

Histogram: 

There are differences in the data because some groups may have not been able to recover all the copper and some may have lost some copper through some of the steps. Another reason could be that some groups may have not subtracted the weight of the filter paper when they were measuring all the stages. 

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Alloys are used to modify the properties of a particular metals to make it get properties of its combined substance. Some uses of alloys include: medals, bells, machine parts, plumbing, screws, and wires. Alloys properties can change for example, when copper and zinc mix it produces brass which has a golden color diffferent from copper and zinc color and brass is harder than copper.

2SDS pg. 204 #7-13

7) An alloy is a solid combination of atoms of two or more metals.

8) An example of two alloys I use regularly are bronze and steel.

9) A nonmetal that is a component of both steel and stainless steel is carbon.

10)  Ni3Al, is a low-density, strong metallic alloy of nickel and aluminum used as a component of jet aircraft engines.

11) Metallloids are mostly semi-conductors and are located on the right of the periodic table.

12) Three elements commonly used for doping semiconductors are phosphorus, arsenic, and aluminum.

13) The primary use of the products of semiconductor technology is for computers and other electronics.

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The difference between O2 and O3 is that O2 is oxygen, which makes up 20% of the air you breathe and O3 is ozone, which is a gaseous substance found in the upper layers of our planet's atmosphere, as well as in some of the air pollution associated with cities.