Chapter 9 And 11 Review Questions

Question 1

3

equation 9.1 contains an n on both sides of the equation. The one on the left is a coefficient; the one on the right is a subscript. Explain

Answer 1

The coefficient tells how many there is of something
The subscript tells what it is that is shown

Question 2

5

describe how each of these strategies would be expected to affect the properties of polyethylene. Also provide an explanation at the molecular level for each effect.
A) increasing the length of the polymer chain
B) aligning the polymer chains with one another
C) increasing the degree of branching in the polymer chain

Answer 2

A) at the molecular level, increasing the length of the polymer chain would increase its molar mass and the extent of its interactions with neighboring chains. This would be expected to give the polymer slightly more density, rigidity, melting point, and more strength.
B) at the molecular level, aligning polyethylene chains with one another means that the structure is more crystalline and highly ordered. This would be expected to give the polymer slightly more density, rigidity, and more strength. The melting point would also increase
C) at the molecular level, this would be opposite of the previous answer. The structure would be less crystalline, less ordered, and possibly somewhat tangled. This would be expected to make the polymer slightly less dense, less rigid, and not as strong. The melting point would also decrease

Question 3

9

determine the approximate number of H2C=CH2 monomeric units, n, in one molecule of polyethylene with a molar mass of 40,000 g/mol. How many carbon atoms are in this molecule?

Answer 3

Each ethylene monomer has a molar mass of 28 g/mol. To determine the number of monomers in the polymer divide 40,000 (the molar mass of the polymer) by 28 (the molar mass of the monomer). The result is 1428 monomers, or 1400 to two significant figures. To determine the number of carbon atoms present in the polymer, note that each monomer contains two carbon atoms (H2C=CH2). Accordingly, the polymer contains 2x1,428 carbon atoms, or 2856 carbon atoms. In round numbers, there are roughly 3000 carbon atoms.

Question 4

11

vinyl chloride polymerizes to form PVC in several different arrangements, as shown in figure 9.9. Which example is shown in the drawing?

Answer 4

this is tail-to-tail, heah-to-head arrangement of PVC formed from three monomer units

Question 5

12

Here are two segments shown in a drawing of a larger PVC molecule. Do these two structures represent the same arrangement? Explain your answer by identifying the orientation in each arrangement

Answer 5

these are different. the top segment represents the “head-to-tail, head-to-tail” arrangement. The Cl atoms in each case are on alternate carbon atoms. It make no difference if the atom is on the “top” or the “bottom” of the chain (these positions are equivalent). In contrast, the bottom segment is “head-to-head, tail-to-tail.” the cl atoms are on adjacent carbon atoms.

Question 6

14 Which of the “Big Six” most likely would be used for these applications?

A) clear soda bottles
B) opaque laundry detergent bottles
C) clear, shiny shower curtains
D) tough indoor - outdoor carpet
E) plastic baggies for food
F) packaging “peanuts”
G) containers for milk

Answer 6

A) PET, polyethylene terephthalate
B) HDPE, high-density polyethylene
C) PVC, polyvinyl chloride (“vinyl”)
D) PP, polypropylene
E) LDPE, low-density polyethylene
F) PS, polystyrene
G) HDPE, high-density polyethylene

Question 7

17

name the functional group(s) in each of these monomers:
A) styrene
B) ethylene glycol
C) terephthalic acid
D) the amino acid in which R = H
E) hexamethylenediamine
F) adipic acid

Answer 7

A) Phenyl group, alkene
B) hydroxyl group, (or alcohol)
C) phenyl group, carboxylic acid
D) amine, carboxylic acid
E) amine
F) carboxylic acid

Question 8

22

The Dow Chemical Company won a Presidential Green Chemistry Challenge Award for developing a process that uses a CO2 as the blowing agent to produce Styrofoam packaging material.
A) What is a blowing agent?
B) What compound does CO2 likely replace in the process, and why is this substitution environmentally beneficial?

Answer 8

A) the blowing agent is a gas (or a substance capable op producing a gas) used to manufacture a foamed plastic. For example, a blowing agent is used to produce Styrofoam from PVC
B) carbon dioxide can replace the CFCs or the HCFCs that once were used as blowing agents. Although CO2 is a greenhouse gas, it still is preferable because CFCs and HCFCs both deplete the ozone layer and are potent greenhouse gases.

Question 9

24

recycled products now are beginning to provide the origin of the recycled material.
A) give examples of postconsumer content and or preconsumer content.
B) do recyclable products contain recycled materials?

Answer 9

A) postconsumer content includes all types of waste: newspapers, cardboard, foam cups, packing peanuts, 2-liter bottles, and plasticware. Preconsumer content includes waste created in the manufacturing process, such as scraps of fabric, plastics, paper, wood, and food.
B) not necessarily. For example, most PET soda bottles are made from petroleum products and do not include recycled PET

Question 10

26

currently, many 2-liter beverage bottles are made of PET with polypropylene caps. Why is polypropylene a good choice for a bottle cap? What difficulty does using polypropylene present in recycling of PET bottles?

Answer 10

polypropylene (PP) is a tough plastic and bottle caps need to be tough, standing up to repeated use and not losing shape or their threads. However, PP melts at a higher temperature than PET and has different properties. SO somewhere in the recycling process, PP needs to be separated from PET. In essence, in most cases the caps need to be removed from the bottles.

Question 11

28

the properties of a polymer depend, in part, on which chemical elements it contains. Name three additional things that influence the properties of a particular polymer

Answer 11

Factors other than the chemical composition of the monomer(s) influence the properties of the polymer. These include the length of the chain (the number of monomer units), the three-dimensional arrangement of the chains, the degree of branching in the chain, and orientation of monomer units within the chain (such as heat-to-tail).

Question 12

38

here is a recycling symbol that is more colorful than the standard ones used on many plastic containers.
A) what is PLA?
B) why is corn depicted in the center of the symbol?
C) this symbol is printed in green ink, presumable to convey that this polymer is “green.” Give two reasons why PLA is considered an eco-friendly polymer
D) for each of your reasons in the previous part, provide information counter to your argument

Answer 12

A) PLA stands for polylactic acid, a polymer
B) the monomer of PLA is lactic acid. In the United States, lactic acid is produced from corn.
C) reasons include: corn is a renewable resource, PLA is compostable, PLA is not a petroleum-based monomer
D) Although corn is renewable corn is a crop with many controversies. These include: degradation of the land on which it is grown and the runoff of fertilizers and pesticides in nearby waterways. Although PLA is compostable, this is only the case in industrial composters that most communities do not compose of. It can even degrade slowly if it is not all in the landfill. even though oil is not used in this process, fuels like petroleum are use in growing and transporting corn.

Question 13

46

today some packaging peanuts are made form plant-based materials rather than polystrene foam.
A) starch is one of the options. what is starch and what is its source?
B) name two advantages and two disadvantages of starch packaging peanuts?
C) name an option for disposing of starch packing peanuts

Answer 13

A) starch is polymer of glucose. Many foods are a source of starch including: corn, potatoes, and rice
B) advantages of starch packing peanuts: lightweight, compostable, and made from renewable material. Disadvantages: degrade if the package is wet, made from what can be eaten, less “springy” than polystyrene foam peanuts
C) composting is a very good first option. Although it can sometimes be washed down the drain, this causes it to then need to be removed in a water treatment plant

Question 14

48

DEHP is a plasticizer that is an example of a phthalate, an ester of phthalic acid.
A) What is a plasticizer?
B) Why are plasticizers such as DEHP added to PVC?
C) DEHP has been banned for some uses. Name two and explain why.

Answer 14

A) a plasticizer is a compounds added to a hard or rigid plastic in order to make it softer.
B) DEHP was added to a PVC in order to make it soft and create vinyl products such as boots, shower curtains, clothes, and even flexible tubing for various uses.
C) DEHP has been banned for items that infants may use repeatedly in their mouths like pacifiers. DEHP has been banned in some medical devices and toys for children. DEHP has also been termed controversial because there are many different restrictions set across the world

Question 15

3

macronutrients provide a source of energy and raw materials for your body.
A) name three different types of macronutrients
B) how do macronutrients differ in energy content?

Answer 15

A) three different types of macronutrients are fats, carbohydrates, and proteins
B) fats are the highest in energy content, almost a factor of two higher than carbohydrates and proteins, which are similar in energy content

Question 16

11

using figure 11.7, identify the fat or oil that contains the highest number of grams per tablespoon of
A) polyunsaturated fat
B) total unsaturated fat
C) monounsaturated fat
D) saturated fat

Answer 16

A) flaxseed oil
B) safflower oil
C) safflower oil
D) coconut oil

Question 17

13

name foods in which would be likely to find these carbohydrates?
A) lactose
B) sucrose
C) fructose
D) starch

Answer 17

A) milk (lactose is “milk sugar”)
B) many fruit contain fructose (“fruit sugar”)
C) sucrose (“table sugar) originates from both beets and sugarcane
D) starch is a primary component of potatoes, rice, tapioca, taro root, wheat, corn

Question 18

15

starch and cellulose are both polysaccharides. How are these two compounds similar in terms of their chemical structures? How are they different in terms of our ability to digest them?

Answer 18

both starch and cellulose are polymers in which the monomer is glucose. But the glucose units are hooked together in a different manner. Our bodies possess an enzyme that can digest starch. In contrast, we lack the enzyme that would enable us to digest cellulose. In essence, we can derive nutritional value from a potato but not from a piece of paper.

Question 19

19

chemical names, especially for organic compounds, can give information about the structure of the molecules that these compounds contain. What does the term amino acid suggest about its molecular structure?

Answer 19

the “amino” in amino acid indicates that there is an amine functional group present. The “acid” indicates there is an acidic functional group; in this case, a carboxylic group

Question 20

23

why are people with phenylketonuria able to drink beverages sweetened with sucralose but should avoid those sweetened with aspartame?

Answer 20

phenylketonuria is a disease in which people lack the enzyme necessary to metabolize phenylaline, an amino acid. Without an enzyme, phenylaline accumulates in the body eventually causes problems in brain development. People who are phenylketonurics must carefully limit their intake of food rich in proteins. Although aspartame is a sweetener, it is a dipeptide of aspartic acid and penylalanine. Sucralose, with a chemical strucutre not related to amino acids, does not pose any risk to people with this disease

Question 21

33

the label of a popular brand of soft margarine lists “partially hydrogenated soybean soil” as an ingredient. Explain the term partially hydrogenated. Why must the label report partially hydrogenated soybean oil rather than simply soybean oil

Answer 21

the process of adding hydrogen to an unsaturated molecule to make it saturated.
partial hydrogenation is when some of the c=c are hydrogenated but not all of them

Question 22

35

explain why process of interesterification is a useful alternative to hydrgenation

Answer 22

The process of hydrogenating an oil to “add H atoms” converts some of the C=C double bonds in the oil to C-C single bonds. This is desirable in that it improves the shelf life of the product (and sometimes the spread ability as well). However, hydrogenation produces trans fat as a side-product, a drawback, because trans fats both increase “bad” cholesterol and decrease the “good” cholesterol. Interest eradication also reduces the number of C=C double bonds, but accomplishes this in a way that does not produce trans fat

Question 23

37

some people prefer to use nondairy creamer rather than creamer and milk. Some but not all nondairy creamers use coconut oil derivatives to replace the butterfat in cream. Is a person trying to reduce dietary saturated fats wise to use nondairy creamers such as these. Explain

Answer 23

Based only on the percent of saturated fat in coconut oil relative to the butterfat in cream, this is not a good plan. Coconut oil is 87% saturated fat, but butterfat is only 67% saturated fat. However, if a person uses a smaller quantity of the nondairy creamer than of cream, his or her total amount of saturated fat consumption may be reduced

Question 24

39

your friend wants to cut food cost and has learned that peanut butter is a good protein source. What additional information should your friends consider before eating peanut butter as a major dietary protein source

Answer 24

peanut butter is a good source of protein but is high in fats and oils
on the positive side peanut butter is considered hydrogenated, and peanut oil is largely unsaturated

Question 25

41

American diets depend heavily on bread and other wheat products. A slice of whole wheat (36 g) contains approximately 1.5g of fat (with 0g saturated fat), 17g carbohydrates (with about 1g of sugar), and 3gs of protein
A) calculate the total Calorie Content in a slice of this bread
B) calculate the percent of calories from fat
C) do you consider bread a highly nutritious food? explain your reasoning

Answer 25

A) 1.5g fat * 9Cal/g fat = 10 calories from fat
17g carbohydrate * 4 Cal/g carbohydrate
=70 calories from carbohydrates
3g protein * 4 Cal/carbohydrate = 10 calories from protein
the total number of calories is 90 calories per slice
B) percent calories from fat is
10cal/90cal * 100 = 11%
C) one slice of whole wheat bread qualifies as a nutritious food because it provides a serving of whole grains with few additional Calories from sugars and fats. Remember that if one slice of bread counts for one serving, then a sandwich counts as two servings of bread
- in this question the answers are rounded to the nearest significant figure

Question 26

42

describe three ways in which agriculture is connected to the use of fossil fuels. Which aspects will eating locally alter?

Answer 26

• the production of chemicals for fertilizers is important because farming is not properly transporting food. Fossil fuels are used to make these fertilizers
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