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1. I feel as though everything worked really well together, especially the students teaching students method.

2. I would say less homework and instead take more time to understand the concepts.

3. Yes, I think that if we maybe pair up or make small groups we can make little video presentations and play them for the class.

4.  We can use blogs more effectively by becoming more creative with the backgrounds and maybe post more gifs and pictures.

5. I think that the instructor should check for compleation not for a grade because sometimes we don't know every single answer and so grading it for a grade I feel would be unfair.

6. Maybe more drawings and videos would bring creativty to the class.

Homework Blog 23

1. Repeating units in each structure

a. Monomer: 1

b. Dimer: 2

c. Trimer: 3

d. Polymer: unlimited

3. Natural polymers: cellulose, starch, nucleic acids, peptides

Synthetic polymers: polyethylene, polypropylene, polyurethane, polystyrene

6. The term "unsaturated" is used to describe alkenes and alkynes because they have other than single bonds within their structures. Alkenes have a double bond and Alkynes have a triple bond.

13. 

11. 

a. II

b. III

c. I

d. II

12. The other 75% is lost in heat, which is why the engine is so inefficient.

Homework Blog 22

31. 

a. Propane, C3H8

b. Pentane, C5H12

32. The suffix -ane indicates that hexane is an alkane.

33. Yes, each of these molecules is an isomer of the other. They all have of 5 carbon atoms and 12 hydrogen atoms, but appear to be different because of the arrangement of those atoms. These three molecules are structured isomers of one another, for they have identical molecular formulas but different arrangements of atoms.

34. See drawing.

35. Butane (C4H10) is the shortest-chain alkane that can demonstrate isomerism- alkanes with four or more carbon atoms can be demonstrated as straight-chain structures, branched-chain structures, and ring structures.

36. Both representations are correct because of their different arrangements of atoms that do not change the identical molecular formulas of the molecule. This would make the molecules structural isomers of each other.

37.

a. See drawing.

b. The branched-chain molecule would have the lower boiling point. Since the straight-chain molecule has greater molecule-to-molecule contact, it has a stronger intermolecular force than the branched-chain molecule, resulting in a higher boiling point.

38.

a. A short, straight chain would have a lower boiling point because of decreased molecule-to-molecule contact than the longer boiling point. The bonds of this chain would be easier to break than a longer straight chain.

b. A short, branched chain would have the lower boiling point. Although the bonds of a branched chain are easier to break than those of a straight chain, it would be more difficult to break more molecular bonds within the long chain, resulting in a higher boiling point.

c. A short, branched chain would have a lower boiling point. Straight chains have stronger intermolecular forces that hold together each molecule in contact; where as bonds between branched chains are more breakable due to the decreased intermolecular molecular forces between them.

1. Petroleum is sometimes considered "buried sunshine" because as a fossil fuel, it originates from biomolecules of prehistoric plants and animals. The energy released by burning petroleum represents energy originally captured from sunlight by these prehistoric green plants during photosynthesis; "buried sunshine".

2.

a. Potential energy is energy of position, or stored energy ready to be released. An example of potential energy is the energy within an unreleased winded up spring toy.

b. Kinetic energy is energy related to motion. A car rolling down a hill is an example of kinetic energy.

3. Chemical energy, another form of potential energy, is stored within the bonds in chemical compounds. When an energy-releasing reaction takes place, the bonds break and reactant atoms reorganize to form new bonds and release energy. If more energy is released than originally started with, the reaction is exothermic, but if less energy is released than originally started with, the reaction is endothermic.

4. A molecule of butane has more potential energy; it has more carbons than methane and a higher boiling point than methane. The bonds of butane are harder to break than the bonds of methane, resulting its higher potential energy.

5.

a. Potential

b. Potential

c. Kinetic

d. Potential

e. Kinetic

6. Energy is required to break chemical bonds because it is what causes the reactant bonds to break and reorganize to form new bonds and energy.

7.

a. Exothermic energy is released than is required to begin the chemical reaction.

b. Endothermic energy is required to crack large hydrocarbon molecules than is released.

c. Endothermic takes more energy to digest a candy bar than the energy released after digestion.

8. The product of a burning candle yields more energy than the energy to begin the reaction with an unlit candle. Since more energy is let off than required to begin the reaction, burning a candle is an exothermic reaction.

9. See drawing.

10. The law of conservation of energy states that energy is neither created nor destroyed in any mechanical, physical, or chemical processes.

Blog Question

Water has a high boiling point and alcohol has a low boiling point; therefore, when the mixture was heated the alcohol vaporized first and left the distillation flask. The alcohol then condenses back into a liquid and is able to be collected and then the water boils. 

Blog Homework 21

1. Infrared radiation is mostly heat energy. Exposure to it is not as harmful as exposure to ultraviolet light. Ultraviolet light is the most energetic form of sun radiation and it can cause sunburns, skin cancer, and can even sterilize materials by killing bacteria and destroying viruses.

2. Visible solar radiation provides the energy needed for photosynthesis and it is the red visible scattering of light during sunset that makes sunsets look red. 

3. Less water vapor leads to less greenhouse gas because there is water vapor in dry and arid regions. Infrared radiation is not stored and reradiated back into the atmosphere from the entering of UV and visible light that is transformed into IR radiation in clouds. 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.

4. (a) The daytime temperatures would be much cooler, because with less greenhouse gases there is less infrared radiation stored and reradiated back into the atmosphere. Less stored heat energy would enter throughout the day. (b) Without stored heat energy in the atmosphere, nights would be very cold.

1. 1 kg.

2. 0.40 L of fuel.

3. 72 L of fuel would be consumed.

4. Atmospheric CO2 levels have increased due to clearing forests, combustion of cuttings and scrap timber, and the burning of fossil fuels.

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

6. The policy may seem necessary to some people in order to preserve the prevent pollution to help the atmosphere.

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

2. Petroleum is a nonrenewable resource and a material that is used as fuel that can be converted to gasoline. It can be used as heat sources, deliver energy to generate electricity, generate energy, and produce useful every day products.

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, grease, heavy oils, wax, petroleum jelly, road oils, asphalt, and petroleum coke.

8.   (a) Water bottle, sports equipment, clothing, and others.    (b) A water bottle can be made out of aluminum. Clothing can be made of cotton. Limbs can be made out of copper.

10. (a) The Middle East has the most petroleum.    (b) Central Asia, Far East, and Oceania have the least petroleum.

11.  (a) Central Asia, North America,  Far East, and Oceania, Western Europe, and Eastern Europe consume more petroleum than they possess.    (b) The Middle East, Africa, and Central and South America consume a smaller proportion of petroleum than they possess.

12. When two liquids are insoluble with each other density separates them.

13. Water and acetone are the easiest to separate from each other by distillation. Water has the highest boiling point and acetone has the lowest of the four substances.

15.

     

16. Fractional distillation does not separate each substance in crude oil. It produces fractions. Fractional distillation is a process that consists of a distillation column and different temperatures in order to separate solutions. Simple distillation uses evaporation and condensation.

17. 

-Light: motor gasoline and refined oil

-Intermediate: Gas oil, furnace oil, and diesel fuel oil.

-Heavy: Grease, heavy oils and wax, and cracking stock.

18. The highest boiling point range would be removed at the bottom. This is because they are thick liquids that never vaporize. They drain from the tower’s base.

19. After fractional distillation use distillation.

20. Methane, pentane, hexane, and octane. 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, which allows both atoms to fill their outer shells completely.

22. Atoms with filled electrons are stable and tend to be chemically uncreative. Noble gases are atoms with filled outer electron shells so they are not reactive because they do not loose or gain electrons.

23. They should share it just like repelling electrons, the dogs pull away from each other, but are still connected by the bond they share with the sock holding them together.

26. (a) It shows the makeup of a molecule and how high the boiling point is. A molecular formula just shows the amount of atoms each element in the formula possesses.   (b) The structure of a formula show how strong molecular bonds within the formula are along with the boiling point of the formula.

27.

(a) 

(b) 

28. It only shows four dots because the four dots represent the valence electrons, located on the outer 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

Homework Blog 20

1. The frequency of electromagnetic radiation and energy are directly proportional. Wavelength of electromagnetic radiation and energy are inversely proportional.

2. The word spectrum is a good descriptor of the types of energy found in electromagnetic radiation because the spectrum shows the vast range of energy.

3. Visible light is useful in plant photosynthesis while other forms of electromagnetic radiation are not because visible radiation can only supply energy needed for the reactions by energizing electrons in chemical bonds.

4.

a. Infrared, visible, ultraviolet

b. Infrared radiation affects living things because it is essentially heat energy, which provides warmth. Visible radiation affects living things through photosynthesis because it can energize electrons in chemical bonds. Although ultraviolet radiation can cause sunburns, skin cancer, and can kill bacteria and destroy viruses, it can affect living things in a positive way because some exposure fuels production of Vitamin D.

5. Ultraviolet light is effective for the use of sterilizing lab protective goggles because UV-C radiation can kill bacteria and destroy viruses, unlike visible light.

6. Infrared radiation is absorbed by carbon dioxide and water vapor, and the energy is then projected back to earth. The majority of visible radiation directed towards earth travels to Earth's surface on a clear day. UV-C radiation is absorbed in the stratosphere before reaching earth's surface and most UV-A and UV-B radiation is absorbed by the stratospheric ozone layer.

7. The more greenhouse gases produced, the more infrared radiation is absorbed. There is then more energy on earth’s surface, hotter water, and a much hotter planet.

8.

a. Asphalt warms up more quickly when exposed to sunlight because right when solar radiation makes contact, it is reflected back into space. Lake water does reflect light, but also absorbs and stores heat.

b. Water may act like greenhouse gases and absorb infrared light. Asphalts directly reflect light sources back into space.

14. Atmospheric CO2 and water vapor help maintain moderate temperatures on Earth's surface because CO2 blocks out the infrared light, sustaining the correct amounts of UV visible light entering Earth.

15.

a. Natural processes: decay of plants/animals, absorption of CO2 -- Human activities: burning fossil fuels, bonfires

b. Natural processes: plants decay, cows let out methane -- Human activities: bonfires, methane

16. 

Temperature increase- methane and CO2 increase

Temperature decrease- ozone increase and solar energy decrease

17. On a sunny winter day, a greenhouse with transparent glass walls is much warmer than is a structure with opaque wooden walls because the glass permits visible and UV light to enter the greenhouse but at the same time does not allow the reradiated infrared radiation leave the greenhouse.

18. 

a. 

b. 

19. Three chemical reservoirs of carbon atoms are limestone, fossil fuels, and plant decay.

20. Over time, a particular carbon atom can be part of the atmosphere, biosphere, lithosphere, and hydrosphere. A carbon atom from a decayed fish was in the ocean water, which was then used to water a plant. The carbon that makes up the plant can be released when it decays and then fossilized. It can after get pumped from the ground and used as petroleum gas. The gas may fuel cars and later pollute the atmosphere.

Data Analysis

1)

A. Due to the fact that CuO is not reactive with HCl, but copper is, adding 50 mL HCl to our beaker of 0.99 g of CuO showed us that unconverted Cu formed at the bottom of the beaker; therefore, the primary reaction was incomplete.

B. It is a possibility that by exposing more of the copper to oxygen, a better reaction would have happened and more copper oxide would have formed.

2)

A. Although we thought all 0.99 grams of powdered copper reacted when we heated it, retrieving the unconverted Cu, we discovered that in actuality, 0.33 g reacted.

B. 0.33/0.99 x 100% = 33%

33% of the total copper sample reacted when heated.

3)

A. Zn: + Cu^2+ → Zn^2+ + Cu:

B.

§  Zn was oxidized

§  II. Cu was reduced

§  III. Zn is the reducing agent

§  IV. Cu is the oxidizing agent

4)

A. The zinc became kind of brick color, and began to crust and crumble.

B. The reasoning behind this is because zinc is more reactive than copper; thus, the zinc caused copper to reduce as it oxidized.

C. When the color of the solution was fairly clear, it was an indication that the Cu2+ ions in the solution had reduced into solid Cu the zinc had oxidized.

5)

A. The resources used in the recovery process were Cu2+ and Zn.

B. Cu2+ reduced to Cu, and Zn oxidized to Zn2+ within the solution.

Blog Question

Alloys are metallic substances composed of a mixture or a metallic solid solution of two or more metals. Some of their uses consist of transportation (Al), construction (Al), ductility (Cu), aircraft turbine engines (Ni), and high corrosion resistance (Cu). The properties of alloys can change. The hardness of steel formed from carbon and iron can depend on the amount of carbon added and the processing it underwent.