Chapter 21

Identify three applications of hydrocarbons as a source of energy and raw materials.

Name an organic compound and explain what an organic chemist studies.

Compare and contrast saturated and unsaturated hydrocarbons.

Describe the process of fractional distillation.

Infer Some shortening products are described as "hydrogenated vegetable oil," which are oils that reacted with hyrrogen in the presence of a catalyst. Form a hypothesis to explain why hydrogen reacted with the oils.

Challenge Draw the structures of the following branched-chain alkanes. a. 2,3-dimethyl-5-propyldecane b. 3,4,5-triethyloctane

Challenge Draw the structures of the following cycloalkanes. a. 1 -ethyl-3-propylcyclopentane b. 1,2,2,4-tetramethylcyclohexane

Describe the main structural characteristics of alkane molecules.

Describe the general properties of alkanes.

Draw the molecular structure for each of the following. a. 3,4-diethylheptane \(\quad\) c. 1-ethyl-4-methylcyclohexane b. 4-isopropyl-3-methyldecane \(\quad\) d. 1,2-dimethylcyclopropane

Interpret Chemical Structures Why is the name 3-butylpentane incorrect? Based on this name, write the structural formula for the compound. What is the correct lUPAC name for 3-butylpentane?

Challenge Draw the structure of 1,3-pentadiene.

Describe how the molecular structures of alkenes and alkynes differ from the structure of alkanes.

Identify how the chemical properties of alkenes and alkynes differ from those of alkanes.

Draw the molecular structure of 4-methyl- 1,3-pentadiene and 2,3-dimethyl-2-butene.

Infer how the boiling and freezing points of alkynes compare with those of alkanes with the same number of carbon atoms. Explain your reasoning, then research data to see it supports your idea.

Predict What geometric arrangement would you expect from the bonds surrounding the carbon atom in alkanes, alkenes, and allynes? (Hint: VSEPR theory can be used to predict the shape.)

Draw all of the structural isomers possible for the alkane with the molecular formula \(\mathrm{C}_{6} \mathrm{H}_{14}\) . Show only the carbon chains.

Explain the difference between structural isomers and stereoisomers.

Infer why living organisms can make use of only chiral form of a substance.

Evaluate A certain reaction yields 80\(\%\) trans-2-pentene and 20\(\%\) cis-2-pentene. Draw the structures of these two geometric isomers, and develop a hypothesis to explain why the isomers form in the proportions cited.

Challenge Draw the structure of 1,4-dimethylbenzene.

Explain benzene's structure and how it makes the molecule unusually stable.

Explain how aromatic hydrocarbons differ from aliphatic hydrocarbons.

What is the main characteristic of an organic compound?

What characteristic of carbon accounts for the large variety of organic compounds?

Name two natural sources of hydrocarbons.

Explain what physical property of petroleum compounds is used to separate them during fractional distillation.

Explain the difference between saturated hydrocarbons and unsaturated hydrocarbons.

How many electrons are shared between two carbon at oms in each of the following carbon-carbon bonds? a. single bond b. double bond c. triple bond

Molecules are modeled using molecular formulas, structural formulas, ball-and- stick models, and space-filling models. What are the advantages and disadvantages of each model?

Describe the characteristics of a homologous series of hydrocarbons.

Fuels Name three alkanes used as fuels and describe an additional application for each.

Draw the structural formula of each of the following. a. ethane \(\quad\) c. propane b. hexane \(\quad\) d. heptane

How does the structure of a cycloalkane differ from that of a straight-chain or branched-chain alkane?

Freezing and Boiling Points Use water and methane to explain how intermolecular attractions generally effect the boiling and freezing points of a substance.

Draw full structural formulas for the following compounds. a. heptane b. 2-methylhexane c. 2,3-dimethylpentane d. 2,2-dimethylpropane

Draw condensed structural formulas for the following compounds. Use line structures for rings. a. 1,2-dimethylcyclopropane b. 1,1-diethyl-2-methylcyclopentane

Explain how alkenes differ from alkanes. How do alkynes differ from both alkenes and alkanes?

The name of a hydrocarbon is based on the name of the parent chain. Explain how the determination of the parent chain when naming alkenes differs from the same determination when naming alkanes.

Draw condensed structural formulas for the following compounds. Use line structures for rings. a. 1,4-diethylcyclohexene b. 2,4-dimethyl-1-octene c. 2,2-dimethyl-3-hexyne

How are two isomers alike, and how are they different?

Describe the difference between cis- and trans-isomers in terms of geometrical arrangement.

What are the characteristics of a chiral substance?

Light How does polarized light differ from ordinary light, such as light from the Sun?

Draw condensed structural formulas for four different structural isomers with the molecular formula \(\mathrm{C}_{4} \mathrm{H}_{8} .\)

Draw and label the \(c i s-\) and \(t r a n s-\) isomers of the mole-cule represented by the following condensed formula. $$\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CHCH}_{2} \mathrm{CH}_{3}$$

What are carcinogens?

Draw the structural formula of 1,2-dimethylbenzene.

How many hydrogen atoms are in an alkane molecule with nine carbon atoms? How many are in an alkene with nine carbon atoms and one double bond?