Blog Question

Blog about global warming.

Global warming is caused by an increase in global temperatures. Many scientists believe that climate change is for sure happening, and that human activities are the primary driver. Increase in temperature is also caused by the increase in human greenhouse gas concentrations. Global warming may also cause an increase in sea levels because as more glaciers melt, they add to the amount of water in big bodies of water. It may also cause and increase in soil moisture in North America.

4S4SBS (p.360) #1-8 and 4SBS (p.361) #14-20

7/21/13

4SBS #1-8
1. The frequency of electromagnetic radiation and its energy are proportional; high frequency radiation is also high- energy radiation.

2. The word spectrum is 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 chemical bonds, which provides energy needed for photosynthesis to occur.

4. a. The main types of electromagnetic radiation in order of increasing energy: inferred radiation, visible radiation, and ultraviolet radiation.
    b. Inferred radiation affects living things because it is basically heat radiation, which causes the surface and temperature to be warmer. Visible radiation affects living things by having an impact on photosynthesis. It has an impact on photosynthesis because it can energize electrons in some chemical bonds. And ultraviolet radiation affects living things because it causes sunburns, which leads to skin cancer, and kills and destroys bacteria and viruses. Even though ultraviolet radiation causes this, it is necessary by humans in moderate doses to provide vitamin D.

5. Ultraviolet light is often used to sterilize chemistry laboratory protective goggles and not visible light because ultraviolet light (UV-C radiation) is the most energetic and can kill bacteria and destroy viruses. This is because UV-C photons have enough energy to break covalent bonds, which causes chemical changes to occur in materials exposed to radiation.

6. Infrared radiation are absorbed by two greenhouse natural gases, carbon dioxide and water vapor, that redirect the energy back into earth. For visible radiation, on a clear day 90% of the visible region of solar radiation directed toward Earth travels down to Earth. Of ultraviolet radiation, UV-C radiation is absorbed in the stratosphere before reaching earth's surface and most UV-A and UV-B radiation us absorbed by the stratospheric ozone layer, and does not reach the earth's surface.

7. Two main effects of solar radiation that reached Earth's surface are more water vapor and hotter water, which results in a hotter Earth in all. This is caused when more greenhouse gases are produced, like carbon dioxide and water vapor, more infrared radiation is absorbed. This then causes more energy  to be reradiated on earth's surface.

8. a. Lake water reflects light, as well as absorbing and storing heat. Asphalt, like snow, sand, or concrete, warms up when exposed to sunlight; therefore, heating. This is because when solar radiation strikes these materials, it is reflected and illuminated back into space.


4SBS #14-20
14. Atmospheric CO2 and water vapor help maintain moderate temperatures because they both greenhouse gases, which means they would absorb infrared radiation, which would help maintain temperature.

15. a. Increase the amount of CO2 in the atmosphere:
          Natural process: human breathing and bacterial decay
          Human process: agricultural and industrial process and the burning of fossil fuels
      b. Increase the amount of CH4 in the atmosphere:
          Natural process: decomposition product of plant and animals
          Human process: refining fossil fuels and raising livestock

16. The changes in the composition of the atmosphere that would cause the average surface temperature to increase would be an increase in greenhouse/ atmospheric gases, which causes higher pressure. What would cause the average surface temperature to decrease would be the decrease of greenhouse/atmospheric gases, which causes lower pressure.

17. A green house with transparent glass walls is much warmer than a structure with opaque wooden walls because the inflered light cant escape glass. It is basically how greenhouse gases work because they change UV and visible radiation to infrared radiation in clouds and reflects heat energy within Earth.

18. a. How the greenhouse works

      b. The global greenhouse effect works

19. Three chemical reservoirs of carbon atoms are atmospheric CO2 gas, solid calcium carbonate in limestone, natural gas, and organic molecules.

20. Carbon atoms could be part of the atmosphere as a gas due to photosynthesis. They could be part of the lithosphere due to plant or animal decay. Or they could be part of the hydrosphere as limestone.

Lab Report: Retrieving Copper

LAB REPORT:

Retrieving Copper

7/19/13

Charlie, Georgie, Ben 

Dr. Forman

Lab Questions:

Group Data Table

1. a. The observational  evidence that leads us to think that the reaction was incomplete because when you heat copper, atoms of copper don't leave, they just change.

    b. I could revise the procedure so that more copper (II) oxide could form by heating copper for a longer amount of time, so more copper can combine with oxygen.

2. a. The mass of the original powdered copper sample that reacted when we heated it was 96%. 

    b. The percent of the total copper sample that reacted was 85%.

3. a.  Cu2+ + Zn --> Cu + Zn2+

    b. i. The reactant that was oxidized was Zn.

       ii. The reactant that was reduced was Cu2+.

      iii. The reducing agent is Zn.

      iv. The oxidizing agent is Cu2+.

4. a. When we added zinc to the solution there was a reaction and caused a dark red color, and was brittle, like a copper color.

   b. What caused the changes we observed in the solution was the theory that a more reactive metal will cause a reaction in a less reactive solution. And in this cases zinc is more reactive than copper.

   c. Once the solution changed to a clear color, it proved that Cu2+ ions int he solution reduced to Cu. And the Zn had oxidized to become Zn2+.  

5. a. The resources that were used up in this recovery process was Cu2+ ions and solid Zn.

    b. Cu2+ reduced to Cu, and Zn oxidized to Zn2+ in the solution.

Aggregated Class Data:

Before our experiment to retrieve copper, the class as a whole believed that when we heated copper that we converted all the copper, but really only about 30% of the copper converted. And 50%-70% of the copper didn't converted. In the unconverted copper, most groups got about 0.70g of  unconverted copper and other groups got more around 0.60g. However, when we converted copper, most groups got about 0.24g, and many more got a higher number around 0.34g. After we retrieved copper we realized that atoms are never destroyed or made, but just changed.

Class Aggregated Data

Blog Question

The uses of alloys and how their properties change.

Alloys are solid combination of atoms of two or more metals. To modify properties of a particular metal is to form it into an alloy. Some uses include transportation, construction, jet aircraft engines, high corrosion resistance, and sometimes have the ability to conduct an electrical current.

2SDS (p.204) #7-13

7/18/13

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

8. Two alloys I use regularly are steel and carat-gold. Steel are alloys that consist of iron and carbon. Steal is used for cars and kitchens. Carat-gold is an alloy that is made up of gold, copper, and silver. It is used for jewelry.

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

10. Chromium- platinum (Cr3Pt) is a very hard alloy that forms the basis of some commercial razor blade edges.

11. Elements that behave as semi-conductors are called metalloids. They are located at the break of metals and nonmetals. They portray qualities of both metal and nonmetals. Metals are known to be reactive, and nonmetals are not reactive.

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

13. The primary use of the products of semi conductor technology is to allow computers to process digital information. Some semi-conductor devices include transistors and integrated circuits used in commuters and other electronics.

Blog Question

Explain the difference between allotropes (O2 vs. O3).

Allotropes are different forms of an element that each have distinctly different physical or chemical properties. Oxygen exists as two allotropes, which are O2 and O3. O2 is known as oxygen gas, and makes up 20% of the air we humans breathe. On the other hand, O3 is known as ozone, and is a gaseous substance found in the upper layers of our planet's atmosphere, and can cause air pollution.

2SDS (p.204) #1-6

7/17/13

1. Allotropes are different forms of the same element that each have distinctly different physical or chemical properties.

2. Oxygen and silicon are two other elements other than carbon that form allotropes.

3. a. A diamond is an extremely hard substance, has a high melting point, not electrically conductive, and is expensive because it is rare. Coal is combustible (burn) and cheap. Pencil lead (graphite) is electrically conductive and common; therefore, cheap.
    b. There properties are different because of the way the atoms of elements are linked together and organized.
    c. The difference in the cost of these items is due to the high melting point, hardness, and rarity of the diamond, which causes the diamond to be more expensive. Where as in graphite and coal they are more reactive and common, which makes them cheaper.

4. Engineered materials are materials made by scientists and engineers to enhance the natural materials through manufacturing methods. However, natural materials can't be controlled, so you basically get what is there.

5. Two advantages of using high ceramics in high- temperature applications are they can operate at higher temperatures and still keep their strength. They are also durable, meaning they can withstand pressure. Two disadvantages of using ceramics is that they are brittle and can break easily if exposed to rapid temperature change, like hot to cold in engines.

6. Two examples of properties that can be modified in plastics to make them useful for new applications are one plastic can be both hard and soft. Like polyethylene, which can be made to display either soft and pliable properties (squeezing a bottle for water) or crafted to be hard and brittle (glasslike). Plastic can also be made into optical fibers, which will replace copper wires in phones and data transmission lines for communication.