?Two carbon atoms connected by a single bond can rotate relative to each other. This

How do two structural isomers differ from each other?

How are two structural isomers similar to each other?

What physical property of hydrocarbons is used in fractional distillation?

What types of hydrocarbons are more abundant in higher-octane gasoline?

To how many atoms is a saturated carbon atom bonded?

What is the difference between a saturated hydrocarbon and an unsaturated hydrocarbon?

How many multiple bonds must a hydrocarbon have in order to be classified as unsaturated?

What kind of ring do aromatic compounds contain?

What is a heteroatom?

Why do heteroatoms make such a difference in the physical and chemical properties of an organic molecule?

Why are low-formula-mass alcohols soluble in water?

What distinguishes an alcohol from a phenol?

What distinguishes an alcohol from an ether?

Which heteroatom is characteristic of an amine?

Do amines tend to be acidic, neutral, or basic?

Are alkaloids found in nature?

What are some examples of alkaloids?

Which elements make up the carbonyl group?

How are ketones and aldehydes related to each other? How are they different from each other?

How are amides and carboxylic acids related to each other? How are they different from each other?

From what naturally occurring compound is aspirin prepared?

What happens to the double bond of a monomer participating in the formation of an addition polymer?

What is released in the formation of a condensation polymer?

Why is plastic wrap made of polyvinylidene chloride stickier than plastic wrap made of polyethylene?

Two carbon atoms connected by a single bond can rotate relative to each other. This ability to rotate can give rise to numerous conformations (spatial orientations) of an organic molecule. Is it also possible for two carbon atoms connected by a double bond to rotate relative to each other? Hold two toothpicks side by side and attach one jellybean to each end such that each jellybean has both toothpicks poked into it. Hold one jellybean while rotating the other. What kind of rotations are possible? Relate what you observe to the carbon–carbon double bond. Which structure of Figure 19.7 do you suppose has more possible conformations: butane or 2-butene? What do you suppose is generally true about the ability of atoms connected by a carbon–carbon triple bond to twist relative to each other?

A property of polymers is their glass transition temperature, \(T_{g}\), which is the approximate temperature below which the polymer is hard and rigid, but above which the polymer is soft and flexible. The \(T_{g}\) of polyethylene is a chilly -125\({ }^{\circ} \mathrm{C}\), which is why polyethylene food wrap is flexible at ambient temperatures. Consider the two polymers polyethylene terephthalate (PETE) and polystyrene (PS). Which do you suppose has the higher \(T_{g}\)? Dip some plastics of these two polymers in boiling water to find out. A common polymer used to make chewing gum is polyvinyl acetate, with a Tg of about 28\({ }^{\circ} \mathrm{C}\), which is below body temperature but above room temperature. That’s why most chewing gums are hard until they soften up in your warm mouth. Drink ice water while chewing gum and note how it quickly hardens. Text Transcription: T_g ^circC

Isopropyl alcohol, also known as rubbing alcohol, is very toxic if ingested. This is because it acts to destroy the digestive proteins and other important biomolecules in your stomach. Do this activity to see firsthand the destructive action of isopropyl alcohol on proteins. Crack open an egg and place the egg white and the yolk into two separate bowls. Pour a capful of isopropyl alcohol into the egg white and observe what happens. In the second bowl, stir the yolk with a fork. Add another capful of isopropyl alcohol to the stirred yolk and observe what happens. The same sort of destruction would occur to your own stomach proteins, as well as various tissues, upon ingesting the isopropyl alcohol. Not good! Our skin, however, is more impervious to the destructive powers of isopropyl alcohol, which therefore serves as a good topical antiseptic.

Rank the following molecules in order of the phase they form at room temperature: solid, liquid, gas.

Rank the following hydrocarbons in order of increasing number of hydrogen atoms:

Rank the following hydrocarbons in order of increasing number of hydrogen atoms:

Rank the following organic molecules in order of increasing solubility in water:

Rank the following organic molecules in order of increasing solubility in water:

What property of carbon allows for the formation of so many different organic molecules?

Why does the melting point of hydrocarbons increase as the number of carbon atoms per molecule increases?

Draw all the structural isomers for hydrocarbons having the molecular formula \(\mathrm{C}_{6} \mathrm{H}_{14}\). Text Transcription: H_14

How many structural isomers are shown here?

According to Figure 19.3, which has the higher boiling point: gasoline or kerosene?

The temperatures in a fractionating tower at an oil refinery are important, but so are the pressures. Where might the pressure in a fractionating tower be greatest: at the bottom or at the top? Defend your answer.

There are five atoms in the methane molecule, \(\mathrm{CH}_{4}\). One of these five atoms is a carbon atom, which means the molecule is 1/5 3 100 5 20% carbon. What is the percent carbon in ethane, \(\mathrm{C}_{2} \mathrm{H}_{6}\)? propane, \(\mathrm{C}_{3} \mathrm{H}_{8}\)? In butane, C4H10? Text Transcription: CH_4 C_2H_6 C_3H_8

Do heavier hydrocarbons tend to produce more or less carbon dioxide upon combustion than do lighter hydrocarbons? Why?

What do these two structures have in common?

What do the compounds cyclopropane and propene have in common?

What are the chemical formulas for the following structures?

Remember that carbon–carbon single bonds can rotate, whereas carbon–carbon double bonds cannot rotate. How many different structures are shown below?

Which of the structures shown in the previous question are either the cis- or the trans-isomers of 3-methyl-2- pentene? Circle them.

Identify the following functional groups in this organic molecule: amide, ester, ketone, ether, alcohol, aldehyde, amine.

What must be added to a double bond to transform it into an alcohol? Would this be an example of oxidation or reduction? (See Figure 18.20)

What do phenols and carboxylic acids have in common?

What is the difference between a ketone and an aldehyde?

An ether is to an alcohol as an ester is to (a) a phenol. (b) a carboxylic acid. (c) an amide. (d) an ether.

Why do ethers typically have lower boiling points than alcohols?

What is the percent volume of water in 80-proof vodka?

One of the skin-irritating components of poison oak is tetrahydrourushiol: The long, nonpolar hydrocarbon tail embeds itself in a person’s oily skin, where the molecule initiates an allergic response. Scratching the itch spreads tetrahydrourushiol molecules over a greater surface area, causing the zone of irritation to grow. Is this compound an alcohol or a phenol? Defend your answer.

Cetyl alcohol, \(\mathrm{C}_{16} \mathrm{H}_{34} \mathrm{O}\), is a common ingredient of soaps and shampoos. It was once commonly obtained from whale oil, which is where it gets its name (cetyl is derived from the word cetacean, which is used to refer to members of the family of mammals that includes whales, dolphins, and porpoises). Review the discussion of soaps, in Section 16.5 and then draw the likely chemical structure for this alcohol. Text Transcription: C_16H_34O

A common inactive ingredient in products such as sunscreen lotions and shampoo is triethylamine, also known as TEA. What is the chemical structure for this compound?

A common inactive ingredient in products such as sunscreen lotions and shampoo is triethanolamine. What is the chemical structure for this tri-alcohol?

The phosphoric acid salt of caffeine has the structure This molecule behaves as an acid in that it can donate a hydrogen ion, created from the hydrogen atom bonded to the positively charged nitrogen atom. What are all the products formed when 1 mole of this salt reacts with 1 mole of sodium hydroxide, NaOH, a strong base?

Draw all the structural isomers for amines having the molecular formula \(\mathrm{C}_{3} \mathrm{H}_{9} \mathrm{~N}\). Text Transcription: H_9N

In water, does the following molecule act as an acid, a base, neither, or both?

If you saw the label phenylephrine . HCl on a decongestant, would you worry that consuming it would expose you to the strong acid hydrochloric acid? Explain.

The amino acid lysine is shown below. What functional group must be removed in order to produce cadaverine, as shown in Figure 19.18?

An amino acid is an organic molecule that contains both an amine group and a carboxyl group. At an acidic pH, which structure is most likely? Explain your answer.

Suggest an explanation why aspirin has a sour taste.

Benzaldehyde is a fragrant oil. If stored in an uncapped bottle, this compound will slowly transform into benzoic acid along the surface. Is this an oxidation or a reduction?

What products are formed upon the reaction of benzoic acid with sodium hydroxide, NaOH? One of these products is a common food preservative. Can you name it?

The disodium salt of ethylenediaminetetraacetic acid, also known as EDTA, has a great affinity for lead ions, \(\mathrm{Pb}^{2+}\). Why? Can you think of any useful applications of this chemistry? Text Transcription: Pb^2+

Would you expect polypropylene to be more dense or less dense than low-density polyethylene? Why?

Hydrocarbons release a lot of energy when ignited. Where does this energy come from?

The polymer styrene–butadiene rubber (SBR), shown below, is used for making tires as well as bubble gum. Is it an addition polymer or a condensation polymer?

Citral and camphor are both 10-carbon odoriferous natural products made from the joining of two isoprene units plus the addition of a carbonyl functional group. Shown below are their chemical structures. Find and circle the two isoprene units in each of these molecules.

Many of the natural product molecules synthesized by photosynthetic plants are formed by the joining together of isoprene monomers via an addition polymerization. A good example is the nutrient beta-carotene. How many isoprene units are needed to make one beta-carotene molecule? Find and circle these units within the beta-carotene structure shown below.

The solvent diethyl ether can be mixed with water but only by shaking the two liquids together. After the shaking is stopped, the liquids separate into two layers, much like oil and vinegar. The free-base form of the alkaloid caffeine is readily soluble in diethyl ether but not in water. Suggest what might happen to the caffeine of a caffeinated beverage if the beverage was first made alkaline with sodium hydroxide and then shaken with some diethyl ether.

Alkaloid salts are not very soluble in the organic solvent diethyl ether. What might happen to the free-base form of caffeine dissolved in diethyl ether if gaseous hydrogen chloride, HCl, were bubbled into the solution?

Go online and look up the total synthesis of the anticancer drug Taxol. With this major accomplishment in mind, discuss the relative merits of specializing in a single area versus becoming an expert in many different areas. When in life do we have the opportunity of simultaneously narrowing our focus while expanding our horizons?

What is a copolymer?

What is a copolymer?