Farewell Blog

I originally took this class thinking it would be a waste of my summer, but i ended up having a really good time with my friends. I surprisingly learned a lot and i discovered that chemistry actually interests me. Im really happy I took this class.

Feedback

1.  This summer what has worked well is that we review the nights reading in class so we understand what we read. What also worked is that we have time in class to do homework so we do not have as much when we get home and are not as overwhelmed.

2. For next years course I recommend that the nights when we have very little homework we can get ahead so that in week 6 we are not so overwhelmed with homework.

3. I think we can make the economist more interesting if we can branch out to other science articles because a lot of kids in the class repeat articles because we run out of options.

4. We can use blogs more effectively if we focus on not just doing the homework on them, but also add extra things related to what we are learning for the fun of it and not for the letter grade.

5. The instructor should check that we did all the homework but he/she should not grade on correct or incorrect answers because in homework we make mistakes because we haven't talked about it in class yet.

6. I think we should have more experiments that are fun and creative and we should have art projects related to chemistry instead of homework and tests everyday. I think we should also travel away from the book as much and learn the same things in other ways. It gets really boring reading chapters every night and then taking a quiz on it the next day. We could all get a section that night then the next day each of us teach from that section to the whole class. It is said that if you teach something you learn it better.

HW #14

SCS #1, 3, 6, 13

1.   (a)  1        (b)  2          (c)  3         (d)  500-20,000

3. Four examples of natural polymers are celluloid, shellac, clay, stone, and many others. Some examples of synthetic polymers are paint components, fabrics, rubber, insulating materials, foams and many others.

6. Unsaturated hydrocarbons have one or more double or triple bonds. Alkenes, which contain carbon-carbondouble bonds are described as unsaturated hydrocarbons. Not all carbon atoms are bonded to their full capacity with four other atoms. Because of their double bonds, alkenes are more chemically reactive, which makes them better builder molecules than alkanes.

13. 

SBS #11-12

11.  (a) ii        (b) iii       (c) i

12. The other 75% is lost to the surrounding as thermal energy.

Blog Question

Fossil fuels are our primary energy supply. It consist of coil, oil, and natural gases. They are also nonrenewable. This is why we need alternative energy. One example of alternative energy are hybrids. The batteries are recharged while driving, through conversion of the car's kinetic energy into stored chemical potential energy. They switch from gasoline engines to electric motors. Electric vehicles reduce the amount of waste that is being produced from the burning of gas being released in the air.

HW #13

3SAS #31-38

31. (a) Propane; molecular formula: C3H8
      (b) Pentane; molecular formula: C5H12

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

33. Yes because they all have the same molecular formulas, but just a different arrangement of atoms.

34.

35. Butane is the shortest-chain alkane that demonstrates isomerism. It is and alkane with four or more carbon atoms that can be straight-chain structures, branched-chain structures, or ring structures.

36. Both representations are correct because it doesn't change the molecular formula.They are structural isomers.

37. (a) 

      (b) The straight-chain has the lowest boiling point because it has a weaker intermolecular force.

38. (a) A short-straight chain has the lowest boiling point because of the weaker intermolecular forces. This makes the bonds easier to break apart.     (b) A short-branched chain has lowest boiling point because longer branched-chains have a stronger molecular forces.     (c) A long, straight chain has a higher boiling point because it has a stronger intermolecular forces.

3SBS  #1-10

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

2.  a. Potential energy is energy of position or stored energy ready to be released. One example is the energy within an unreleased winded up spring toy.
     b. Kinetic energy is energy related to motion. An example of this is a car rolling down a hill.

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

4. A molecule of butane has more potential energy because it has more carbon atoms and a higher boiling point than methane. The bonds of butane are harder to break apart, which results in a higher potential energy.

5. (a) Potential energy    (b) Potential energy    (c) Kinetic energy    (d) Potential energy    (e) Kinetic energy

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

7. (a) Exothermic because more heat energy is released than is required to begin the chemical reaction.     (b) It's endothermic because the molecule is being broken up; therefore, energy is being used.
    (c) Endothermic because the molecule is being broken up; therefore energy is being used.

8. More energy is given off than is added, which makes it exothermic.

9.

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. When the mixture is heated the alcohol will vaporize first and leave the distillation flask. The alcohol,then condenses back into a liquid and can  be collected. Then the water boils. Then this water will repeat for the water.

HW #12

p. 341

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.

p. 350

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.

p. 233

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