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

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

Name an organic compound and explain what an organic chemist studies

Identify what each of the four molecular models highlights about a molecule.

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 hydrogen in the presence of a catalyst. Form a hypothesis to explain why hydrogen reacted with the oils.

Interpret Data Refer to Figure 21.6. What property of hydrocarbon molecules correlates to the viscosity of a particular fraction when it is cooled to room temperature?

Use the IUPAC rules to name the following structures. a. CH3 CH3 CH3CHCH2CHCH2CH3 b. CH3 CH3 CH3CCH2CHCH3 CH3 c. CH3CHCH2CH2CHCH2CHCH3 CH3 CH2 CH3 CH3

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

Use IUPAC rules to name the following structures. a. CH3 b. CH2CH3 CH3 CH3 c. CH3CH2 CH2CH3

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.

Name the following structures using IUPAC rules. a. b. c. CH3CHCH2CH2CH3 CH3 CH3CCH3 CH3 CH3 CH3 CH3 CH3 CH2CH3

Describe the general properties of alkanes.

Draw the molecular structure for each of the following. a. 3, 4-diethylheptane c. 1-ethyl-4-methylcyclohexane b. 4-isopropyl-3-methyldecane 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 IUPAC name for 3-butylpentane?

Use the IUPAC rules to name the following structures. a. CH3CH CHCHCH3 CH3 b. CH3CHCH2CH CH2 CH3 CHCCH3 CH3 CH3

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.

Name the structures shown using IUPAC rules. a. CH3 CH CCH2 b. CH3 CH3C CHCH CH2

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 if supports your idea.

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

Draw all of the structural isomers possible for the alkane with the molecular formula C 6 H 14 . Show only the carbon chains.

Explain the difference between structural isomers and stereoisomers.

Draw the structures of cis-3-hexene and trans-3-hexene.

Infer why living organisms can make use of one 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.

Formulate Models Starting with a single carbon atom, draw two different optical isomers by attaching the following atoms or groups to the carbon: H, C H 3 ; C H 2 C H 3 ; C H 2 C H 2 C H 3

Name the following structures. a. CH2CH2CH3 b. CH3 CH2CH3 c. CH3 CH3 CH2CH3

Challenge Draw the structure of 1,4-dimethylbenzene.

Explain benzenes structure and how it makes the molecule unusually stable.

Explain how aromatic hydrocarbons differ from aliphatic hydrocarbons.

Describe the properties of benzene that made chemists think it was not an alkene with several double bonds.

Name the following structures. a. CH3 CH3CH2 CH3 b. CH2CH2CH3 CH2CH3

Explain why the connection between benzopyrene and cancer was significant.

Organic Chemistry Why did Wohlers discovery lead to the development of the field of organic chemistry?

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.

Distillation Rank the compounds listed in Table 21.7 in the order in which they will be distilled out of a mixture. Rank the compounds in order of first to distill to last to distill. Table 21.7 Alkane Boiling Points Compound Boiling Point (C) hexane 68.7 methane -161.7 octane 125.7 butane -0.5 propane -42.1

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 C H2N NH2 O Figure 21.29

Figure 21.29 shows two models of urea, a molecule that Friedrich Whler first synthesized in 1828. a. Identify the types of models shown. b. Is urea an organic or an inorganic compound? Explain your answer.

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 c. propane b. hexane d. heptane

Write the condensed structural formulas for the alkanes in the previous question.

Write the name and draw the structure of the alkyl group that corresponds to each of the following alkanes. a. methane b. butane c. octane

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.

Name the compound represented by each of the following structural formulas. a. CH3CH2CH2CH2CH3 d. CH3 CHCH3 CHCH3 CH3 b. CH3 CH3 CH2CH3 c. H H H C H C H H C H H C H C H H C H H H C H H H

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

Name the compound represented by each of the following structural formulas. a. CH3 CH3 CH3 c. CH3 CH2CH2CH3 b. CH3 CH3CH2 d. CH3 CH3 CH3 CH2CH3

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.

Name the compound represented by each of the following condensed structural formulas. a. CHCH3 CH3 CH3 C c. CH3 b. CH2 CH3CH2 CH3CH2 C d. CH3

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

Name the compound represented by the following condensed structural formula. CH2CH2CH3 CH3CH2 CH2CH3 CH3 C

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?

How do optical isomers affect polarized light?

Identify the pair of structural isomers in the following group of condensed structural formulas. a. CH3CCH2CH2CH3 CH3 CH3 c. CH3CHCHCH2CH3 CH3 CH3 b. CH3CHCH2CH CH3 CH3 CH3 d. CH3CHCH2CHCH3 CH3 CH3

Identify the pair of geometric isomers among the following structures. Explain your selections. Explain how the third structure is related to the other two. a. C CH3 CH2CH2CH3 CH 3 C CH3 b. CH2CH3 CH3CH2 CH3 CH3 C C c. C CH3CH2 CH2CH3 CH 3 C CH3

Draw condensed structural formulas for four different structural isomers with the molecular formula C 4 H 8

Draw and label the cis- and trans- isomers of the molecule represented by the following condensed formula. CH3CH CHCH 2CH3

Three of the following structures are exactly alike, but the fourth represents an optical isomer of the other three. Identify the optical isomer, and explain how you made your choice. a. T Q S C R c. R T S C Q b. T R Q C S d. R T Q C S

What structural characteristic do all aromatic hydrocarbons share?

What are carcinogens?

Draw the structural formula of 1,2-dimethylbenzene.

Name the compound represented by each of the following structural formulas. a. CH3 b.

Do the following structural formulas represent the same molecule? Explain your answer. a. C CH3 CH3 H C H b. C H CH3 H C CH3

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?

The general formula for alkanes is C n H 2n + 2 . Determine the general formula for cycloalkanes.

Manufacturing Why are unsaturated hydrocarbons more useful than saturated hydrocarbons as starting materials in chemical manufacturing?

Is cyclopentane an isomer of pentane? Explain your answer

Determine whether each of the following structures shows the correct numbering. If the numbering is incorrect, redraw the structure with the correct numbering. a. CH3 CH3 2 4 3 1 c. CH3 CH3 1 5 4 3 2 b. d. CH3 4 5 3 2 1 6 CH2CH3

Why do chemists use structural formulas for organic compounds rather than molecular formulas such as C 5 H 12 ?

Which would you expect to have more similar physical properties, a pair of structural isomers or a pair of stereoisomers? Explain your reasoning.

Explain why numbers are needed in the IUPAC names of many unbranched alkenes and alkynes but not in the names of unbranched alkanes.

A compound with two double bonds is called a diene. The name of the structure shown is 1,4-pentadiene. Apply your knowledge of IUPAC nomenclature to draw the structure of 1,3-penadiene. H2C CH CH2 CH CH 2

Determine which two of the following names cannot be correct, and draw the structures of the molecules. a. 2-ethyl-2-butene c. 1,5-dimethylbenzene b. 1,4-dimethylcyclohexene

Infer The sugar glucose is sometimes called dextrose because a solution of glucose is known to be dextrorotatory. Analyze the word dextrorotatory, and suggest what the word means.

Interpret Scientific Illustrations Draw Kekuls structure of benzene, and explain why it does not truly represent the actual structure.

Recognize Cause and Effect Explain why alkanes, such as hexane and cyclohexane, are effective at dissolving grease, whereas water is not.

Explain Use Table 21.8 to construct a statement explaining the relationship between numbers of carbon atoms and boiling points of the members of the alkane series shown

Graph the information given in Table 21.8. Predict what the boiling and melting points of the 11- and 12-carbon alkanes will be. Look up the actual values and compare your predictions to the those numbers. Table 21.8 Data for Selected Alkanes Name Melting Point (C) Boiling Point (C) C H 4 -182 -162 C 2 H 6 -183 -89 C 3 H 8 -188 -42 C 4 H 10 -138 -0.5 C 5 H 12 -130 36 C 6 H 14 -95 69 C 7 H 16 -91 98 C 8 H 18 -57 126 C 9 H 20 -54 151 C 10 H 22 -29 174

Chiral Carbons Many organic compounds have more than one chiral carbon. For each chiral carbon in a compound, a pair of stereoisomers can exist. The total number of possible isomers for the compound is equal to 2 n , where n is the number of chiral carbons. Draw each structure, and determine how many stereoisomers are possible for each compound named below. a. 3,5-dimethylnonane b. 3,7-dimethyl-5-ethyldecane

What element has the following ground-state electron configuration: [Ar]4 s 2 3 d 6 ? (Chapter 5)

What is the charge of an ion formed from the following families? (Chapter 7) a. alkali metals b. alkaline earth metals c. halogens

Write the chemical equations for the complete combustion of ethane, ethene, and ethyne into carbon dioxide and water. (Chapter 9)

Gasoline For many years, a principal antiknock ingredient in gasoline was the compound tetraethyllead. Research to learn about the structure of this compound, the history of its development and use, and why its use was discontinued in the United States. Find out if it is still used as a gasoline additive elsewhere in the world.

Perfume The musk used in perfumes and colognes contains many chemical compounds, including large cycloalkanes. Research and write a short report about the sources used for natural and synthetic musk compounds in these consumer products.

Compare the average PAH concentrations before 1905 and after 1925.

PAH compounds are produced in small amounts by some plants and animals, but most come from human activities, such as burning fossil fuels. Infer why the PAH levels were relatively low in the late 1800s and early 1900s.