Chapter 12 Questions W19 with Answers b PDF

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CHEM-120-Chapter 12-Alkanes: Sample Questions 12.1 Introduction 1. The four hydrogen atoms bonded to the central carbon atom in methane lie at the corners or apexes of a A) rectangle. B) tetrahedron. C) square. D) parallelogram. 2. Which types of compounds are saturated hydrocarbons? A) Alkenes B) Aromatic hydrocarbons C) Alkanes D) Alkynes E) All of the hydrocarbons are unsaturated hydrocarbons. 3. Constitutional isomerism is possible in alkanes only if the number of carbon atoms present is A) 2 or more. B) 3 or more. C) 4 or more. D)an odd number. 4. Which of the following alkane structures contain both secondary and tertiary carbon atoms? A). B) C)

D) No correct response 5. How many hydrogen atoms are present in an acyclic alkane with five (5) carbon atoms? A) 5 B) 7 C) 9 D) 10 E) 12 6. Which formula represents an acyclic alkane? A) C10H18 B) C9H18 C) C12H26

D) C10H20

E) C12H28

7. How many hydrogen atoms are present in a cycloalkane (cyclic alkane) with six (6) carbon atoms? A) 6 B) 8 C) 10 D) 12 E) 14 8. Which molecular formula has the largest number of constitutional isomers? A) C5H12 B) C2H6 C) C6H14 D) All of the molecular formulas above have the same number of constitutional isomers. 9. Which of the following pairs of compounds are constitutional isomers? A)

B)

C)

D)

10. Which of the following compounds is identical to the one shown below?

A)

C)

B)

D)

11. Which of the following is a constitutional isomer of the compound shown below? (C5H10O)

A) C)

B) D)

E) Two of the molecules given are constitutional isomer of the original molecule.

12. Which molecule is a constitutional isomer of the compound (CH3)2CH(CH2)2CH3? A) CH3CH2CH2CH(CH3)2 B) C) D)

12.2 Simple Alkanes 13.

Which of the following could not be the molecular formula for an alkane molecule? A) C6H14 B) C6H16 C) CH4 D) C23H48 Answer: B

14. In which of the following alkanes are 13 covalent bonds present? A)

B)

C)

D) No correct response

15.

The representation CH3CH2CH2CH2CH3 for the alkane pentane is an example of A) a molecular formula B) a condensed formula C) a structural formula D) a skeletal formula

16. How many secondary carbons are in the straight-chain alkane with the formula C4H10? A) 0 B) 1 C) 2 D) 3 E) 4 17. In which of the following alkanes are two secondary carbon atoms present? A)

B)

C)

18. How many quaternary carbons are in this molecule? A) 0 B) 1 C) 4 D) 5

D)

19. What is the classification of each labeled carbon atom in the structure below?

A) C1 is a secondary carbon and C2 is a primary carbon. B) C1 is a tertiary carbon and C2 is a secondary carbon. C) C1 is a secondary carbon and C2 is a tertiary carbon. D) C1 is a primary carbon and C2 is a tertiary carbon. 20. Label each carbon indicated with an arrow as primary, secondary, tertiary or quaternary.

A) C1 is a secondary carbon C2 is a primary carbon B) C1 is a secondary carbon C2 is a tertiary carbon C) C1 is a tertiary carbon C2 is a secondary carbon D) C1 is a secondary carbon C2 is a tertiary carbon

and C3 is a primary carbon. and C3 is a primary carbon. and C3 is a primary carbon. and C3 is a primary carbon..

21. What is the classification of each labeled carbon atom in this structure?

A) C1 is a 1°, C2 is 2°, C3 is a 3°, and C4 is 4°. B) C1 is a 2°, C2 is 3°, C3 is a 3°, and C4 is 4°. C) C1 is a 1°, C2 is 2°, C3 is a 3°, and C4 is 1°. D) C1 is a 2°, C2 is 3°, C3 is a 2°, and C4 is 3°. Answer: B 22. Which represents a condensed structure for a four carbon hydrocarbon? A) CH3CH2CH2CH3 B) C4H10 C) D)

23. Which represents a expanded structure for a four carbon hydrocarbon? A) CH3CH2CH2CH3 B) C4H10 C) D)

24. How many carbon atoms are present in the alkane whose IUPAC name is 2,3,4trimethylpentane? A) five

B) seven

C) eight

D) nine

25. How many hydrogen atoms are present in the molecule 3,4-dimethyloctane A) eighteen C) twenty-two B) twenty D) twenty-four 12.3 An Introduction to Nomenclature 26. This branched alkyl substituent is called:

A) isopropyl B) isobutyl

C) sec-butyl

D) tert-butyl

27. This branched alkyl substituent is called: A) isopropyl B) isobutyl

C) sec-butyl

D) tert-butyl

C) sec-butyl

D) tert-butyl

28. This branched alkyl substituent is called: A) isopropyl B) isobutyl

12.4 Alkane Nomenclature 29. What is the IUPAC name of this compound?

A) 4-propylhexane B) 3-ethyl-2-methylhexane D) 4-ethyl-5-methylheptane

C) 2-methyl-3-ethylhexane

30. What is the IUPAC name of this compound?

A) 4-isopentylnonane B) 3-ethyl-4-propylnonane C) 3,3-dimethyl-4-propylnonane D) 3,3-dimethyl-4-butylnonane 31. Which name represents a valid IUPAC name for an alkane? A) 1,4-diethylheptane B) 4,4-diethyl-2,3,4-trimethylpentane C) 4,4-diethyl-2,3,4-trimethylcycloheptane D) 4,4-diethyl-2,3-dimethylheptane E) More than one of the names is a valid IUPAC name for an alkane. 32. What is the IUPAC name of CH3CH2CH2CH2CH2CH3? A) Butane B) Hexane C) Propane D) Pentane E) Heptane 33. Which of the following alkanes has the IUPAC name 2-methylbutane? A) B)

C)

D)

34. What is the IUPAC name for the following compound? A) 1,3-pentamethylpropane B) 1,1,3,3-tetramethylbutane C) 2,4,4-trimethylpentane) D) 2,2,4-trimethylpentane 12.5 Cycloalkanes 35. A cycloalkene having only one carbon-carbon double bond will have the general formula A) CnH2n+2 B) CnH2n C) CnH2n-2 D) CnH2n-4

36. When the molecular formulas for cyclic and noncyclic alkanes with the same number of carbon atoms are compared, it is always found that the cycloalkane has A) two more hydrogen atoms.

B) the same number of hydrogen atoms. C) two less hydrogen atoms. D) four less hydrogen atoms. 37. Which of the following statements concerning cycloalkanes is correct? A) Molecular formula always fits the general formula C nH2n+2. B) They are not hydrocarbons. C) Each exists in two or more isomeric forms. D) All choices given are incorrect. 38. For which of the following cycloalkanes is cis-trans isomerism possible? A) isobutylcyclopentane C) 1-methyl-1-propylcyclopentane B) ethylcyclobutane D) 1-ethyl-3-propylcyclononane 39.

What is the IUPAC name of this compound? A) Ethyl-methyl-cyclopropane B) Ethyl-2-methylcyclobutane C) 1-ethyl-2-methylcyclobutane D) 1-ethyl-2-methylcyclopropane E) Ethyl-2-methylcyclotriane

40. What is the structure of butylcyclopentane? A)

B)

C)

D)

13.6 Focus on the Environment—Fossil Fuels 41. Which has the highest boiling point? A) Natural gas B) Lubricating oil

C) Gasoline

D) Kerosene

E) Fuel oil

42. Asphalt is a mixture of high molecular weight hydrocarbons. Which solvent would be best for removing asphalt from a newly paved road off the bottom of a pair of shoes? A) Water B) Octane C) Methanol, CH3OH D) NaCl(aq)

13.7 Physical Properties 43. Which alkane has the lowest boiling point? A) Octane B) Butane C) Ethane

D) Hexane

E) Propane

44.

Which of the following is a general physical property of alkanes? A) high solubility in organic solvents B) less volatile than water C) most are solids at room temperature D) few are nonpolar molecules

45. Which of the following statements concerning the boiling points of specific alkanes is correct? A) Hexane has a higher boiling point than heptane. B) Pentane has a higher boiling point than 2-methylpentane. C) Cyclobutane has a higher boiling point than cyclopentane. D) No correct response 46. Which compound has the lowest melting point? A) CH3CH2CH2CH2CH3 B) CH3CH2CH2CH2CH2CH2CH2CH3 C) CH3CH2CH2CH2CH2CH3 D) CH3CH2CH2CH2CH2CH2CH2CH2CH2CH3 47. Branching in an alkane chain decreases surface area. With this in mind, which of the following alkanes has the highest boiling point? A) (CH3)2CHCH2CH2CH2CH2CH3 B) (CH3)2CHCH2CH2CH(CH3)2 C) CH3CH2CH2CH2CH2CH2CH2CH3 D) (CH3)3CC(CH3)3 48. For which of the following alkanes in complete combustion produce CO2 and H2O? A) B) C) D)

Cyclobutene Octane 2,3,3,4,4-pentamethylheptane All alkanes given in the choices produce CO2 and H2O

12.8 Focus on the Environment: Combustion 49. The most important chemical use for alkanes relates to their chemical reaction with A) hydrogen.

B) oxygen.

C) chlorine. D) bromine

50. Which balanced chemical equation represents the incomplete combustion of a hydrocarbon? A) CH3CH2CH3 + 5 O2 → 3 CO2 + 4 H2O B) 2 CH3CH2CH3 + 7 O2 → 6 CO + 8 H2O C) C36H74 + 36 O2 → 36 CO + 37 H2O D) C26H50 + 33 O2 → 16 CO2 + 10 CO + 25 H2O 51. What is term used for reaction of a substance with oxygen or air that causes rapid release of heat and appearance of a flame? A) Oxidation B) Combustion C) Burning D) None of these

52. What alkyl halide is formed when CH3CH3 is heated with bromine, Br2? A) C2Br6 B) CH2=CH2 C) CH3CH2OH D) CH3CH2Br 53. What type of compound is formed with an alkane reacts with light and chlorine, Cl 2? A) Alkene B) Alkyl halide C) Alkyne D) Cycloalkane

CHEM-120-Chapter 12: Answers to Sample Questions 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27.

Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer: Answer:

B C C B D C D C A D E C B C B C B B C C B A C C C D B

28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53.

Answer: C Answer: C Answer: C Answer: D Answer: B Answer: A Answer: D Answer: B Answer: C Answer: D Answer: C Answer: D Answer: C Answer: B Answer: B Answer: C Answer: A Answer: B Answer: A Answer: C Answer: D Answer: B Answer: B Answer: B Answer: D Answer: B...